This PR improves support for rendering markdown documents.

## After the updates


https://github.com/zed-industries/zed/assets/18583882/48315901-563d-44c6-8265-8390e8eed942

## Before the updates


https://github.com/zed-industries/zed/assets/18583882/6d7ddb55-41f7-492e-af12-6ab54559f612

## New features

- @SomeoneToIgnore's [scrolling feature
request](https://github.com/zed-industries/zed/pull/6958#pullrequestreview-1850458632).
- Checkboxes (`- [ ]` and `- [x]`)
- Inline code blocks.
- Ordered and unordered lists at an arbitrary depth.
- Block quotes that render nested content, like code blocks.
- Lists that render nested content, like code blocks.
- Block quotes that support variable heading sizes and the other
markdown features added
[here](https://github.com/zed-industries/zed/pull/6958).
- Users can see and click internal links (`[See the docs](./docs.md)`).

## Notable changes

- Removed dependency on `rich_text`.
- Added a new method for parsing markdown into renderable structs. This
method uses recursive descent so it can easily support more complex
markdown documents.
- Parsing does not happen for every call to
`MarkdownPreviewView::render` anymore.

## TODO

- [ ] Typing should move the markdown preview cursor.

## Future work under consideration

- If a title exists for a link, show it on hover.
- Images. 
- Since this PR brings the most support for markdown, we can consolidate
`languages/markdown` and `rich_text` to use this new renderer. Note that
the updated inline text rendering method in this PR originated from
`langauges/markdown`.
- Syntax highlighting in code blocks.
- Footnote references.
- Inline HTML.
- Strikethrough support.
- Scrolling improvements:
- Handle automatic preview scrolling when multiple cursors are used in
the editor.
- > great to see that the render now respects editor's scrolls, but can
we also support the vice-versa (as syntax tree does it in Zed) — when
scrolling the render, it would be good to scroll the editor too
- > sometimes it's hard to understand where the "caret" on the render
is, so I wonder if we could go even further with its placement and place
it inside the text, as a regular caret? Maybe even support the
selections?
- > switching to another markdown tab does not change the rendered
contents and when I call the render command again, the screen gets
another split — I would rather prefer to have Zed's syntax tree
behavior: there's always a single panel that renders things for whatever
tab is active now. At least we should not split if there's already a
split, rather adding the new rendered tab there.
- > plaintext URLs could get a highlight and the click action

## Release Notes

- Improved support for markdown rendering.

I'd love to take on fixing this but:

1. I don't think this is the right solution - it would be really nice to
have something actionable that I could do when presented with this
message.
2. Should signing in to Copilot be independent from whether it's
enabled? You can only access the sign-in modal when `features.copilot`
isn't disabled, but when `show_copilot_suggestions` is `false` the
server is disabled but you can't sign in. So I guess another solution
might be to just not show the UI if copilot suggestions are disabled?
3. I don't know what other circumstances could trigger the empty modal.
I see `Status::Error` and that seems like it might be important to
surface gracefully?

Would love some thoughts on this

Release Notes:

- Improved UX for enabling Copilot when it's disabled in settings

This PR cleans up the path definitions in `util::paths` following the
Linux merge.

We were using a bunch of target-specific compilation that made these
declarations kind of messy, when really we can limit the conditional
compilation to just the base directories that we use as the basis for
the other directories.

Release Notes:

- N/A

Release Notes:

- N/A

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>
Co-authored-by: Marshall <marshall@zed.dev>

This PR fixes a small typo in the `mark_language_loaded` doc comment.

Release Notes:

- N/A

Added some missing trait functions and `unimplemented` markings

Release Notes:

- N/A

#7363 added support for rendering strikethrough text, so now we can
handle this case in the terminal.

Should close: #7434

Before:

![image](https://github.com/zed-industries/zed/assets/53836821/cb7a4eae-5bc9-425c-974d-07a9f089917a)

After:

![image](https://github.com/zed-industries/zed/assets/53836821/5aaacee2-95bc-4039-972d-96bd7c01ea59)

Release Notes:

- Fixed rendering strikethrough text inside the terminal #7434

Release Notes:

- Fixed a panic in diagnostics with emojis

**or**

- N/A

This PR updates the various spots where we reload the theme to use
`ThemeSettings::reload_current_theme` instead of duplicating the code
each time.

Release Notes:

- N/A

```bash
cargo run -p theme_importer -- dark-plus-syntax-color-theme.json --output output.json
```

Release Notes:

- N/A

---------

Co-authored-by: Marshall Bowers <elliott.codes@gmail.com>

This is a follow up to #7170. Closing the reply to preview overlay is
now configurable with an action (keybinding set escape in the default
keymap).


https://github.com/zed-industries/zed/assets/53836821/d679e734-f90b-4490-8e79-7dfe5407988a


Release Notes:
- N/A

This PR extends the extension directory watcher to also watch and reload
themes defined in extensions.

Release Notes:

- N/A

Co-authored-by: Max <max@zed.dev>

https://github.com/zed-industries/zed/pull/7467 introduced a new
`grammar` field in the language configuration files.
The underlying tree-sitter grammar for Terraform should be `hcl` instead
of `terraform`. This PR fixes that typo.

Release Notes:

- N/A

Release Notes:

- N/A

## Motivation

I :heart: Zed! It's lightning fast and has great UX. I want it to run as
well on all major platforms. I'm currently using Linux most actively.
[Blade](https://github.com/kvark/blade) is a good candidate for
providing GPU access: it supports Vulkan, Metal, and GLES/WebGL. Its
abstraction is extremely thin, while having one of the nicest GPU APIs.
Codebase is also tiny. Checkout [the meetup
recording](https://www.youtube.com/watch?v=63dnzjw4azI&t=623s) from a
year ago.
I believe these projects make a good match :rocket: !

### Why this is a bad idea

If Zed team wants to use off-the-shelf components from Rust ecosystem,
then Blade is certainly at disadvantage here, since it's not widely
used. It would rely on Zed team adding necessary features in a branch,
then maybe upstreaming some of them. That is to say, it's unclear if
this can be avoided with more popular alternatives - being flexible with
any local changes is a good ability.

### Why it's not too bad

Blade uses [WGSL](https://www.w3.org/TR/WGSL) shaders, similar to `wgpu`
and `arcana`, but without the binding decorations. So this aspect of the
product is nicely portable.

## Progress

- [ ] Platforms
  - [x] X11 (via xcb)
    - [ ] input handling
    - [ ] get proper content size
  - [ ] Windows
  - [ ] Replace the existing Metal backend
- [ ] Text System
  - [ ] shaping
  - [ ] glyph rasterization
- [x] Texture atlas
- [ ] Rendering
  - [x] basic primitives
  - [x] path rendering
  - [x] sprite rendering
- [ ] media surfaces
- [ ] CI

## Current status
Zed starts up but crashes on text-system related checks.

![zed-linux-1](https://github.com/zed-industries/zed/assets/107301/ba536218-4d2c-43c9-ae6c-bef69b54bd0c)

This PR adds the initial support for loading extensions in Zed.

### Extensions Directory

Extensions are loaded from the extensions directory.

The extensions directory has the following structure:

```
extensions/
  installed/
    extension-a/
      grammars/
      languages/
    extension-b/
      themes/
  manifest.json
```

The `manifest.json` file is used internally by Zed to keep track of
which extensions are installed. This file should be maintained
automatically, and shouldn't require any direct interaction with it.

Extensions can provide Tree-sitter grammars, languages, and themes.

Release Notes:

- N/A

---------

Co-authored-by: Marshall <marshall@zed.dev>

Co-Authored-By: Remco Smits <62463826+RemcoSmitsDev@users.noreply.github.com>

Github usernames are allowed to contain `-`, but the autocompletion was
not working correctly.
We added `-` as an allowed character for markdown files. We are not
aware of any completions for markdown files, so this should be fine to
add.


Before:

![image](https://github.com/zed-industries/zed/assets/53836821/5b456ed6-3098-48e8-90db-f5f42b4aa535)

After:

![image](https://github.com/zed-industries/zed/assets/53836821/a544f465-0b68-46f5-9a15-83b4c755c3c0)


Release Notes:

- Fixed autocompletion for usernames with dash character in the chat
message editor

Co-authored-by: Remco Smits <62463826+RemcoSmitsDev@users.noreply.github.com>

Use the new installation procedures located at
https://ocaml.org/install.

Release Notes:
- N/A

Release Notes:

- Fixed a bug that caused the window to become unresponsive after
foregrounding.

---------

Co-authored-by: Conrad <conrad@zed.dev>

This PR changes our approach to initializing the `SystemAppearance` so
that we can do it earlier in the startup process.

Previously we were using the appearance from the window, meaning that we
couldn't initialize the value until we first opened the window.

Now we read the `window_appearance` from the `AppContext`. On macOS this
is backed by the
[`effectiveAppearance`](https://developer.apple.com/documentation/appkit/nsapplication/2967171-effectiveappearance)
on the `NSApplication`.

We currently still watch for changes to the appearance at the window
level, as the only hook I could find in the documentation is
[`viewDidChangeEffectiveAppearance`](https://developer.apple.com/documentation/appkit/nsview/2977088-viewdidchangeeffectiveappearance),
which is at the `NSView` level.

In my testing this makes it so Zed appropriately chooses the correct
light/dark theme on startup.

Release Notes:

- N/A

Co-Authored-By: Antonio <antonio@zed.dev>
Co-Authored-By: Thorsten <thorsten@zed.dev>
Co-Authored-By: Mikayla <mikayla@zed.dev>

Release Notes:

- N/A

**or**

- N/A

Co-authored-by: Antonio <antonio@zed.dev>
Co-authored-by: Thorsten <thorsten@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>

Reduce windows build error.

Release Notes:

- N/A

apply theme_name(fallback use "")

Release Notes:

- N/A

<img width="1269" alt="image"
src="https://github.com/zed-industries/zed/assets/18583882/d4c93033-b2ac-4ae0-8e12-457f256ee869">

Release Notes:

- Added support for styling text with strikethrough.

Related: 
- https://github.com/zed-industries/zed/issues/5364
- https://github.com/zed-industries/zed/pull/7345

Reverts zed-industries/zed#7481

This would regress performance because we'd be using the standard
library's hash maps everywhere, so reverting for now.

This highlights dead keys. Example: when in Brazilian keyboard layout
and typing `"` it's now underlined.



https://github.com/zed-industries/zed/assets/1185253/a6b65f7b-1007-473d-ab0f-5d658faa191b



Release Notes:

- Fixed dead keys not being underlined.

Co-authored-by: Antonio <antonio@zed.dev>

Previously it wasn't possible to create a keybinding for this action
because it required an argument.

Now the action takes the active item of the pane and if it's a
multi-buffer the first one.

This also adds a default keybinding for Vim mode: `-` will reveal the
file in the project panel.

Fixes #7485.

Release Notes:

- Added `pane::RevealInProjectPanel` as an action in the command
palette. ([#7485](https://github.com/zed-industries/zed/issues/7485)).

Co-authored-by: Antonio <antonio@zed.dev>

Release Notes:

- N/A

Release Notes:

- N/A

Release Notes:

- Improved Jetbrains keybindings to include cmd+alt+left/right to go
back and forwards between panes rather than the default previous / next
pane

Signed-off-by: James Gee <1285296+geemanjs@users.noreply.github.com>

* fix: avoid panics in case of non-existing path for watching

* fix: copy the themes and plugins

* Revert "add a few more libraries to the linux script"

This reverts commit 7509677003da3398d0df796eca9c5435a12f576e.

* fix: add vulkan validation layers to the system deps

* fix: fix the themes paths

Release Notes:

- N/A

This was originally just to fix
https://github.com/zed-industries/zed/issues/4354, which I did by just
returning the previous offset in `find_boundary`.. but `find_boundary`
is used in the "insert mode" / normal editor too, so returning the
previous boundary breaks existing functionality in that case.

I was considering a new `find_boundary` function just for some of the
vim motions like this, but I thought that this is straightforward enough
and future Vim functions might need similar logic too.

Release Notes:

- Fixed https://github.com/zed-industries/zed/issues/4354

Fixes: #2750
Fixes: #7457



Release Notes:

- Fixed a hang/panic that could happen rendering a double-width
character in a single-width terminal
([#2750](https://github.com/zed-industries/zed/issues/2750),
[#7457](https://github.com/zed-industries/zed/issues/7457)).

We noticed the following message in my logs when trying to debug some
lag when collaborating:

```
2024-02-06T09:42:09-08:00 [ERROR] error handling message. client_id:3, sender_id:Some(PeerId { owner_id: 327, id: 1123430 }), type:GetCompletions, error:no such connection: 0/0
```

That `0/0` looks like a bogus connection id, constructed via a derived
`Default`. We didn't ever find a code path that would *use* a default
`ConnectionId` and lead to this error, but it did seem like an
improvement to not have a `Default` for that type.

Release Notes:

- N/A

Co-authored-by: Marshall <marshall@zed.dev>

When a supporting diagnostic had an empty message, we were accidentally
giving the corresponding block a height of zero lines.

Release Notes:

- Fixed an issue where an editors' lines were not laid out correctly
when showing certain diagnostics.

Co-authored-by: Marshall <marshall@zed.dev>

Feature
- [x] Allow to click on reply to go to the real message
    - [x] In chat
- [x] Show only a part of the message that you reply to
    - [x] In chat
    - [x] In reply preview

TODO’s
- [x] Fix migration
    - [x] timestamp(in filename)
    - [x] remove the reference to the reply_message_id
- [x] Fix markdown cache for reply message
- [x] Fix spacing when first message is a reply to you and you want to
reply to that message.
- [x] Fetch message that you replied to
    - [x] allow fetching messages that are not inside the current view 
- [x] When message is deleted, we should show a text like `message
deleted` or something
    - [x] Show correct GitHub username + icon after `Replied to: `
    - [x] Show correct message(now it's hard-coded)
- [x] Add icon to reply + add the onClick logic
- [x] Show message that you want to reply to
  - [x] Allow to click away the message that you want to reply to
  - [x] Fix hard-coded GitHub user + icon after `Reply tp:`
  - [x] Add tests

<img width="242" alt="Screenshot 2024-02-06 at 20 51 40"
src="https://github.com/zed-industries/zed/assets/62463826/a7a5f3e0-dee3-4d38-95db-258b169e4498">
<img width="240" alt="Screenshot 2024-02-06 at 20 52 02"
src="https://github.com/zed-industries/zed/assets/62463826/3e136de3-4135-4c07-bd43-30089b677c0a">


Release Notes:

- Added the ability to reply to a message.
- Added highlight message when you click on mention notifications or a
reply message.

---------

Co-authored-by: Bennet Bo Fenner <53836821+bennetbo@users.noreply.github.com>
Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

We should prefer referring to local deps via `.workspace = true` from
now on.

Release Notes:

- N/A

With upcoming release of 1.76 I did a check of current +beta (which
seems to already be at 1.77). These would cause CI pipeline failures
once 1.77 is out.

Release Notes:

- N/A

This PR improves the error handling when the `editor: copy permalink to
line` action fails.

Right now if something goes wrong nothing happens, and we don't write
anything to the logs.

This PR makes it so we display a toast when the operation fails with the
error message, as well as write it to the Zed logs.

Release Notes:

- Improved error behavior for `editor: copy permalink to line` action.

This PR removes the placeholder that we previously displayed for the
chat message editor.

With the changes in #7441 we can no longer hit this codepath.

Release Notes:

- N/A