We still need to wire up mouse listeners.

[[PR Description]]

Release Notes:

- N/A

This PR adds support for adding a specific set of mappings from Zed
syntax tokens to VS Code scopes for a particular theme family.

We can use this as a fallback when we aren't otherwise able to rely on
the mappings in the theme importer, as sometimes it isn't possible to
make a specific enough matcher that works across all of the themes.

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- N/A

This PR updates the imported themes to set the background colors for the
various bars (title bar, toolbar, tab bar, status bar).

Release Notes:

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This PR improves the approach we use to match syntax tokens between Zed
and VS Code in the `theme_importer`.

We now use the list of scopes assigned to each Zed syntax token to rank
the possible candidates in the VS Code and then pick the candidate with
the highest rank.

So far this has proved to provide better colors across the board, but
we'll continue to refine the matching over time.

Release Notes:

- N/A

After https://github.com/zed-industries/zed/pull/3507, parsing the app's
semver version from the application plist stopped working, which caused
auto-updates to stop.

I don't think we need to put `-nightly` in the version number: it's
already in the release channel name, which is reported alongside the
version in most cases. For example, the 'About' dialog was saying `Zed
Nightly 2.0.0-nightly`.

I think even without nightly, it would be a good idea to include the
*release channel* name in the datadog alerts that show up in slack.
@JosephTLyons could you look into how to do that?

/cc @SomeoneToIgnore

It breaks our semver parsing, and the release channel is already 'nightly'.

This PR fixes an issues where the hex colors in the generated themes
were not correct.

We're using the [`palette`](https://crates.io/crates/palette) crate to
perform the conversions, as this gives us accurate hex codes that match
the VS Code source themes.

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* [x] restructure titlebar to show facepiles for each collaborator and
their followers
* [x] allow following collaborators by clicking their avatars in the
titlebar
* [x] show grayscale avatar for collaborators not focused on this
project
* [x] show collaborators' microphone activity and muted status in the
titlebar
* [x] in facepile, show leader in front of followers

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This PR updates the `theme_importer` to pull hint colors from VS Code
themes.

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This PR removes the padding from buttons when using `ButtonSize::None`.

This fixes the size of the tab close buttons.

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Co-Authored-By: Marshall Bowers <1486634+maxdeviant@users.noreply.github.com>

This PR extracts a new `Tab` component from the tabs implementation in
the workspace.

This will allow us to reuse this component anywhere that we need to use
tabs.

Like our other newer components, the `Tab` component has a relatively
open API.

It accepts `children` (or `child`) as well as a `start_slot` and
`end_slot` to position content in the slots on either end of the
content. These slots also respect the `TabCloseSide` and will switch
positions based on this value.

<img width="763" alt="Screenshot 2023-12-07 at 12 19 42 PM"
src="https://github.com/zed-industries/zed/assets/1486634/78e4db6a-f807-431e-8777-f52f2631e6ed">

Release Notes:

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Release Notes:

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Release Notes:

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

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

[no-ci]