[[PR Description]]

Release Notes:

- Fixes project panel active state that was incorrectly removed.

Release Notes:

* Fix a bug where project panel entries would not be styled correctly
(preview only)

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

This is a mix of styling and behavioral improvements to the assistant
that we wanted to land before shipping today.

Release Notes:

- N/A

Closes
https://linear.app/zed-industries/issue/Z-1890/save-assistant-conversations-to-the-filesystem
Closes
https://linear.app/zed-industries/issue/Z-2459/cycling-message-roles-on-the-last-empty-message-alters-the-message
Closes
https://linear.app/zed-industries/issue/Z-2460/cycling-role-in-an-empty-message-cycles-wrong-messages-role
Closes https://linear.app/zed-industries/issue/Z-2365/assistant-toolbar
Closes
https://linear.app/zed-industries/issue/Z-2461/always-insert-an-empty-message-at-the-end-of-the-conversation

Release Notes:

- You can now save conversations with the assistant to
`~/.config/zed/conversations` with `cmd-s`. Conversations are also
automatically saved as they are edited.

This is a part of the intensity driven theme rewrite. 

It introduces the `toggle` and `interactive` helper functions to build
Toggle<T> and Interactive<T> styles for interactive elements in the
theme.

This PR also removes the `theme_testbench` crate and related actions.

Huge thanks to @osiewicz and @mikayla-maki for pushing this forward 🙏🏽

Release Notes:

- Updated the style of many interactive elements.

Fixes
https://linear.app/zed-industries/issue/Z-2481/heex-this-snippet-triggers-a-hard-crash

Release Notes:

- Fixed a crash that would sometimes occur when editing a HEEx file
([#1703](https://github.com/zed-industries/community/issues/1703)).

Update the Rose Pine theme family, including new syntax overrides
matching the official theme docs:
https://rosepinetheme.com/palette/ingredients/

Also adds a doc to our internal docs starting to outline how our syntax
highlighting works.

Before:
<img width="626" alt="CleanShot 2023-06-21 at 12 19 17@2x"
src="https://github.com/zed-industries/zed/assets/1714999/5ebe1cd0-1707-483b-a50f-bb53dbf89ba2">

After:
<img width="718" alt="CleanShot 2023-06-21 at 12 18 48@2x"
src="https://github.com/zed-industries/zed/assets/1714999/46b588aa-31a0-4402-934b-e3de7bc2f6b5">

From their site:

![image](https://github.com/zed-industries/zed/assets/1714999/83d4f671-e15f-4423-a01e-b382145e79fb)


Release Notes:

- Updated Rose Pine theme family to better match original theme.

I finally got fed up with being unable to copy error messages. This adds
a click target and tooltip to f8-style diagnostics that copies their
text on click.

Release Notes:

- Added the ability to copy under-line diagnostic errors on click

Closes
https://linear.app/zed-industries/issue/Z-2384/hitting-cmd-enter-in-a-user-or-system-message-should-generate-a

Release Notes:

- Introduced the ability to generate assistant messages for any
user/system message, as well as generating multiple assists at the same
time, one for each cursor. (preview-only)

This is something I've been meaning to rename in SumTree. Was looking at
the code and figure why not now.

This avoids a high cost which appears to be the system rasterizing the
cursor every time we call this, fixes a slowdown when scrolling rapidly
while mouse motion continually attempted to assign the style

Fixes
https://linear.app/zed-industries/issue/Z-2200/editor-scroll-slowdown

Release Notes:

- Improved the performance of scrolling by avoiding unnecessary cursor
changes
([#1597](https://github.com/zed-industries/community/issues/1597)).

This avoids a high cost which appears to be the system rasterizing the
cursor every time we call this, fixes a slowdown when scrolling rapidly
while mouse motion continually attempted to assign the style

Co-Authored-By: Antonio Scandurra <me@as-cii.com>

Closes
https://linear.app/zed-industries/issue/Z-2402/elixir-ls-requires-a-system-elixir-runtime-to-be-installed
Closes
https://linear.app/zed-industries/issue/Z-666/notify-users-that-they-need-go-installed-to-use-go-language-server

Release Notes:

- Added a notification when unable to download the Go language server
because Go is not installed.
- Added a notification when unable to run the Elixir language server
because Elixir is not installed.

Fixes
https://linear.app/zed-industries/issue/Z-2391/text-within-h-isnt-highlighted-the-same-as-in-heex-files
Fixes
https://linear.app/zed-industries/issue/Z-2415/syntax-highlighting-bug-in-strings

Release Notes:

- Fixed some issues with syntax highlighting in Elixir and Heex.

If the release notes are only intended for a specific release channel
only, add `(<release_channel>-only)` to the end of the release note
line.
These will be removed by the person making the release.

Z-2357

I've found a crate that handles both comments and trailing commas in
JSON. It is a fork of `serde_json`, but it is maintained & up-to-date.
Sadly RawValue seems to not play nicely with it; I've ran into
deserialisation issues around use of RawValue. For this PR I've migrated
to `Value` API.

Obviously this is just a point of discussion, not something I'd merge
straight away. There may be better solutions to this particular problem.

I've also noticed that `serde_json_lenient` does not handle trailing
commas after bindings array. I'm not sure how big of an issue that is.

Release Notes:
- Improved handling of trailing commas in settings files.
[#1322](https://github.com/zed-industries/community/issues/1322)

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

Closes
https://linear.app/zed-industries/issue/Z-2408/make-block-splitting-work-with-multiple-cursors

Release Notes:

- N/A

I'd like to follow up to allow roles to be cycled for the selected range
and support multi-cursors, but this is a start and contains a
refactoring, so going to merge.

Release Notes:

- Added the ability to cycle roles in the assistant with `ctrl-r`

Co-Authored-By: Julia Risley <julia@zed.dev>

Closes
https://linear.app/zed-industries/issue/Z-2364/allow-splitting-blocks

Release Notes:

- Added support for splitting messages in the assistant panel using
`shift-enter`. (preview-only)