Closes https://github.com/zed-industries/zed/issues/41168

This PR adds both Tailwind CSS and Ruff (linter for Python) as built-in
features; a banner mentioning this should show up now for these two when
searching for them in the extensions UI.

There will also be a corresponding zed.dev site PR adding a "Ruff is
built-in" card to the zed.dev/extensions page.

Release Notes:

- N/A