Add rs-notify implementation of fs::watch (#9040)

This PR simplifies the Zed file system abstraction and implements
`Fs::watch` for linux and windows.

TODO:
- [x] Figure out why this fails to initialize the file watchers when we
have to initialize the config directory paths, but succeeds on
subsequent runs.
- [x] Fix macOS dependencies on old fsevents::Event crate

Release Notes:

- N/A

crates/gpui/src/platform/linux/wayland/client.rs

@@ -281,7 +281,7 @@ impl Client for WaylandClient {
             CursorStyle::ResizeUp => "n-resize".to_string(),
             CursorStyle::ResizeDown => "s-resize".to_string(),
             CursorStyle::ResizeUpDown => "ns-resize".to_string(),
-            CursorStyle::DisappearingItem => "grabbing".to_string(), // TODO linux - couldn't find equivalent icon in linux
+            CursorStyle::DisappearingItem => "grabbing".to_string(), // todo(linux) - couldn't find equivalent icon in linux
             CursorStyle::IBeamCursorForVerticalLayout => "vertical-text".to_string(),
             CursorStyle::OperationNotAllowed => "not-allowed".to_string(),
             CursorStyle::DragLink => "dnd-link".to_string(),