PR to get zed2 into main.

Because we have taken the approach of porting crates by renaming them to
`-2` we will need to manually reapply any changes that were made to
ported crates since the `zed2` branch diverged from master.

I think this is the list of PRs that may need changes ported manually.
Any changes to the following crates may need to be moved from crate `x`
to `x2` for each of the following crates: `audio call client copilot db
feature_flags fs fuzzy gpui install_cli language lsp prettier project
rpc settings storybook terminal theme ui zed`.

- [x] f75eb3f62 Conrad Irwin (origin/main, origin/HEAD, main) Merge
branch 'more-signing' (17 hours ago)
- [x] 832026a0a Julia Limit language server reinstallation attempts
(#3177) (18 hours ago)
- [x] 4539cef6d Julia Capture language server stderr during startup/init
and log if failure (#3175) (21 hours ago)
- [x] e6f2288a0 Conrad Irwin Don't use function_name in vim tests
(#3171) (2 days ago)
- [x] f67f42779 Mikayla Maki Rename IIFE to maybe (#3165) (2 days ago)
- [ ] 90f65ec9f Max Brunsfeld Remove logic for multiple channel parents
(#3162) (2 days ago)
- [ ] 4f859e025 Conrad Irwin link to channel notes (#3167) (2 days ago)
- [ ] b8bd070a8 Conrad Irwin Fix panic by disallowing multiple room
joins (#3149) (3 days ago)
- [ ] cc9e92857 Max Brunsfeld Guest roles (#3140) (3 days ago)
- [x] b090cefdd Kirill Bulatov Rework prettier tests (#3160) (3 days
ago)
- [ ] ff497810d Kyle Caverly move keychain access into semantic index as
opposed to on init (#3158) (3 days ago)
- [x] 2b95db087 Conrad Irwin Fix infinite loop in select all (#3154) (3
days ago)
- [ ] a5836b033 Max Brunsfeld Add chat mentions and a notifications
panel (#3121) (4 days ago)
- [ ] ef1a69156 Kyle Caverly update semantic search to use keychain as
fallback (#3151) (6 days ago)
- [x] 26638748b Kirill Bulatov Move prettier parsers data into languages
from LSP adapters (#3150) (6 days ago)
- [ ] 0dae0f602 Conrad Irwin pixel columns (#3052) (7 days ago)
- [x] cc7df91cc Julia Whoops (#3146) (7 days ago)
- [x] 808976ee2 Julia Magic incantations for Tailwind autocomplete in
more languages (#3141) (7 days ago)
- [ ] cc390ba86 Conrad Irwin Start writing role to database (#3120) (10
days ago)
- [ ] 2795091f0 Kyle Caverly Introduce Context Retrieval in Inline
Assistant (#3097) (10 days ago)
- [x] b168bded1 Conrad Irwin New entitlements: (#3118) (10 days ago)
- [x] 247cdb1e1 Joseph T. Lyons Fix telemetry-related crash on start up
(#3131) (11 days ago)
- [ ] 2323fd17b Julia Autocomplete docs (#3126) (2 weeks ago)
- [x] 16d9d77d8 Kirill Bulatov Update diagnostics indicator when
diagnostics are udpated (#3128) (2 weeks ago)
- [ ] 634202340 Kirill Bulatov Remove zed -> ... -> semantic_index ->
zed Cargo dependency cycle (#3127) (2 weeks ago)

Note: this list does not include any PRs that did not change crates that
have been converted; it also does not include any commits that were
pushed directly to master.

### To figure out what needs migrating, run:

```
git diff COMMIT^..COMMIT -- crates/audio crates/call crates/client crates/copilot crates/db crates/feature_flags crates/fs crates/fuzzy crates/gpui crates/install_cli crates/language crates/lsp crates/prettier crates/project crates/rpc crates/settings crates/storybook crates/terminal crates/theme crates/ui crates/zed
```

I'm not sure these are strictly necessary, but it will make porting
tests easier to have them.

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

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

Co-Authored-By: Kirill <kirill@zed.dev>

In gpui1 we used to do this even outside of top-level contexts, but not
sure we should make tests work that differently to the main app.

Co-Authored-By: Kirill <kirill@zed.dev>

The entity map needs to be able to distinguish between the case when
the entity_id is waiting to be dropped, and when it is completely gone.

Before 8bc207141, it assumed that entity_ids in dropped_entity_ids could
be re-used. This caused `take_dropped` to error because the slot had
been overwritten. The fix there caused weak handles to allow upgrading
a reference count from 0, which could resurrect items in
`dropped_entity_ids` which caused them to be dropped twice.

We could allow weak items to upgrade from 0, and delete from
dropped_entity_ids, but that seemed more complicated than necessary.

Ports https://github.com/zed-industries/zed/pull/3191 to zed2

Deals with zed-industries/community#2191
Fix Zed starting too many prettier installations in the beginning, and not being able to format the config files.

Deals with https://github.com/zed-industries/community/issues/2191

Fix Zed starting too many prettier installations in the beginning, and
not being able to format the config files.

Release Notes:

- Fixed prettier not being able to format Zed's config files and spawning excessive prettier installations

Adds an `Entity` trait for abstracting over `View`s and `Model`s, and
implements it for the `subscribe()` and `observe()` APIs.

The last commit also includes a fun experiment I added, using the
`Result` type to return the owned model handles back to the caller in
the case of downcast failure, inspired by the `binary_search*` methods.

Part of https://github.com/zed-industries/zed/pull/3128 that is possible
to apply now.

@SomeoneToIgnore I had to port
https://github.com/zed-industries/zed/pull/3150 to zed2 in the process,
giving you a heads-up

Don't pass a render function separately from the view.

Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Mikayla <mikayla@zed.dev>
Co-authored-by: Antonio <as-cii@zed.dev>

Part of: 

- https://github.com/zed-industries/zed/pull/3174

Release Notes:

- N/A