Prevent deadlocks when two clients perform a request to each other

This prevents deadlocks when e.g., client A performs a request to client B and
client B performs a request to client A. If both clients stop processing further
messages until their respective request completes, they won't have a chance to
respond to the other client's request and cause a deadlock.

This arrangement ensures we will attempt to process earlier messages first, but fall
back to processing messages arrived later in the spirit of making progress.

Update project metadata when releasing a worktree's weak handle

When a project was getting unshared, we would remove invisible worktrees
from the project's state without notifying the server, which was causing
the randomized tests to fail.

This commit calls `Project::remove_worktree` when a worktree's handle gets
released. Doing so ensures that we update both our local metadata database
as well as the state on the server.

Don't trigger hover popover action when mouse is over context menu

Report running language servers when sharing project for the first time

Show upgrade required message when reconnecting after a protocol change

Co-Authored-By: Max Brunsfeld <max@zed.dev>

Co-authored-by: Antonio Scandurra <me@as-cii.com>

Fix error when worktree has no file extensions

Co-authored-by: Antonio Scandurra <me@as-cii.com>

hide hover on editor blur

Co-authored-by: Antonio Scandurra <me@as-cii.com>

Add an API that returns the most active zed users and the projects where they've been active

Highlight files ending in `mdx` as Markdown

This is clearly a stopgap solution but it'll make our life easier
while hacking on zed.dev.

Enhance auto-closing bracket behavior

Replace "Remove Folder from Project" label with "Remove from Project`

Fix project leak in contacts panel

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