This PR adds the initial support for loading extensions in Zed.
### Extensions Directory
Extensions are loaded from the extensions directory.
The extensions directory has the following structure:
```
extensions/
installed/
extension-a/
grammars/
languages/
extension-b/
themes/
manifest.json
```
The `manifest.json` file is used internally by Zed to keep track of
which extensions are installed. This file should be maintained
automatically, and shouldn't require any direct interaction with it.
Extensions can provide Tree-sitter grammars, languages, and themes.
Release Notes:
- N/A
---------
Co-authored-by: Marshall <marshall@zed.dev>
On a .zig files , the `CMD-/` keybinding don't work,
In the language config its the only language with '//' type comment that
is written in singular without array.
This fixed the problem, so i assume it was just a typo
Release notes:
- Fixed line comment continuations and Editor::ToggleComments for Zig, Haskell and PureScript.
