This reverts commit 5c75450a77b0579649bbf79365c9cef5a2c1110f.

This is a PR I built for a friend of a friend at StrangeLoop, who is
making a much better LSP for elixir that elixir folks want to experiment
with. This PR also improves the our debug log viewer to handle LSP
restarts.

TODO:
- [ ] Make sure NextLS binary loading works.

Release Notes:

- Added support for the experimental Next LS for Elxir, to enable it add
the following field to your settings to enable:

```json
"elixir": {
    "next": "on"
}
```

Release Notes:

- Fixed clicking a code action only ever performing the first action in
the list rather than the one clicked on.

This reverts commit 0a491e773b689a74f96b7555070cf5a3bf245543.

For github.com/zed-industries/community#1021

Release Notes:
- Fixed the code action popup menu not scrolling as selection moves.

Add buffer path to the prompt.

Z-2903

Release Notes:
- Added a "Save all/Discard all" prompt when closing a pane with
multiple edited buffers.

Improve settings interface to local LSP

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

This PR restructures the `ui` crate into just `elements` and
`components`.

This was already done on the `gpui2-ui` branch, just getting it onto
`main`.

Release Notes:

- N/A

---------

Co-authored-by: Nate Butler <nate@zed.dev>

This PR mainlines the `Icon` and `IconButton` changes from the
`gpui2-ui` branch.

Release Notes:

- N/A

Co-authored-by: Nate Butler <nate@zed.dev>

This PR updates the storybook CLI to support displaying all of the
available stories.

The `--help` flag will now show a list of all the available stories:

<img width="1435" alt="Screenshot 2023-09-22 at 6 11 00 PM"
src="https://github.com/zed-industries/zed/assets/1486634/284e1a24-46ec-462e-9709-0f9b6e94931f">

Inputting an invalid story name will also show the list of available
stories:

<img width="1435" alt="Screenshot 2023-09-22 at 6 10 43 PM"
src="https://github.com/zed-industries/zed/assets/1486634/1ce3ae3f-ab03-4976-a06a-5a2b5f61eae3">

Release Notes:

- N/A

This PR scaffolds the `Toolbar` and `Breadcrumb` components.

Right now they both just consist of hardcoded data.

<img width="846" alt="Screenshot 2023-09-22 at 4 54 00 PM"
src="https://github.com/zed-industries/zed/assets/1486634/70578df2-7216-42d2-97ef-d38b83fb4a25">

<img width="799" alt="Screenshot 2023-09-22 at 4 46 04 PM"
src="https://github.com/zed-industries/zed/assets/1486634/73ca3d8a-baf9-4ed4-b4c4-279c674672a3">

Release Notes:

- N/A

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

This PR updates the UI component stories to label the various states
that they are in.

Release Notes:

- N/A

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

This PR improves the error message when `FontCache.load_family` attempts
to load a font that is not present on the system.

I ran into this while trying to run the `storybook` for the first time.
The error message indicated that a font family was not found, but did
not provide any information as to which font family was being loaded.

### Before

```
   Compiling storybook v0.1.0 (/Users/maxdeviant/projects/zed/crates/storybook)
    Finished dev [unoptimized + debuginfo] target(s) in 8.52s
     Running `/Users/maxdeviant/projects/zed/target/debug/storybook`
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: could not find a non-empty font family matching one of the given names', crates/theme/src/theme_settings.rs:132:18
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
libc++abi: terminating due to uncaught foreign exception
fish: Job 1, 'cargo run' terminated by signal SIGABRT (Abort)
```

### After

```
   Compiling storybook v0.1.0 (/Users/maxdeviant/projects/zed/crates/storybook)
    Finished dev [unoptimized + debuginfo] target(s) in 7.90s
     Running `/Users/maxdeviant/projects/zed/target/debug/storybook`
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: could not find a non-empty font family matching one of the given names: `Zed Mono`', crates/theme/src/theme_settings.rs:132:18
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
libc++abi: terminating due to uncaught foreign exception
fish: Job 1, 'cargo run' terminated by signal SIGABRT (Abort)
```

Release Notes:

- N/A

Co-Authored-By: Nathan Sobo <nathan@zed.dev>

This PR removes the need for writing manual mappings in the `FromStr`
implementation for the `StorySelector` enum used in the storybook CLI.

We are now using the
[`EnumString`](https://docs.rs/strum/0.25.0/strum/derive.EnumString.html)
trait from `strum` to automatically derive snake_cased names for the
enums.

This will cut down on some of the manual work needed to wire up more
stories to the storybook.

Release Notes:

- N/A

This PR puts the `Theme` returned from the `theme` function behind an
`Arc`.

### Motivation

While working on wiring up window focus events for the `TitleBar`
component we ran into issues where `theme` was holding an immutable
borrow to the `ViewContext` for the entirety of the `render` scope,
which prevented having mutable borrows in the same scope.

### Explanation

To avoid this, we can make `theme` return an `Arc<Theme>` to allow for
cheap clones and avoiding the issues with the borrow checker.

Release Notes:

- N/A

Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>

This PR factors out the bulk of the boilerplate required to setup a
story in the storybook out into separate components.

The pattern we're using here is adapted from the "[associated
component](https://maxdeviant.com/posts/2021/react-associated-components/)"
pattern in React.

Release Notes:

- N/A

Reorganized assistant/semantic_index crates and introduced AI crate to
include shared functionality.

Release Notes:

- Moved most of the Assistant functionality from ai crate to assistant
crate
- Moved interaction with embedding providers from semantic_index to ai
crate