Override `performKeyEquivalent` to handle key events

This lets us bypass the application menu and invoke the event handler
in Zed first. If that doesn't handle the event, the application menu
item corresponding to the shortcut will be actioned. Prior to this
commit the opposite would happen, which would dramatically limit the
throughput at which we could handle events.

Determine `Buffer::is_dirty` based on the rope's fingerprint

This is calculated in `Rope` and uses the `bromberg_sl2` homomorphic
hash function to determine the fingerprint of a single chunk and
compose each chunk fingerprint into a single fingerprint for the entire
rope that is equivalent to hashing all the rope's bytes at once.

Themes in app menu

Disable auto-indent entirely for markdown

Return focus to the workspace center on escape

Toggle search options via the keyboard

Use word boundaries instead of syntax to infer completion edit ranges

Cap context menu's width to cover at most 70% of the window

Open a buffer for every language server error when clicking on status

Add some tooltips to aid discoverability

Autoscroll to newest selection when adding it via the cursor

Replace `pane::Split` action with `Split{Left,Up,Right,Down}`

This allows us to show them in the command palette.

Fix surrounding text with bracket pairs with multiple selections

This was probably a regression that was introduced with the new batched
`Buffer::edit` API and was caused by providing selection ranges in a
non-ordered fashion (we were passing all the starts first and then all the
ends).

With this commit we are adding a unit test to verify the behavior of
`Editor::surround_with_bracket_pair` and changing the order in which
we pass edit ranges to respect the selection order.

Exclude staff from metrics and start tracking active projects

Now that we track active projects, if nothing happens to the store
during the activity timeout we would still serve some old metrics
that may not account for the staleness of a project.

This commit changes it so that we grab a mutable reference to the store
before serving the metrics, which has the side effect of updating
all the metrics.

An active project is defined as a project where there has been at
least a buffer edit, a join request/response, or a follow update
in the last minute.