Move "async move" a few characters to the left in cx.spawn() (#26758)

This is the core change:
https://github.com/zed-industries/zed/pull/26758/files#diff-044302c0d57147af17e68a0009fee3e8dcdfb4f32c27a915e70cfa80e987f765R1052

TODO:
- [x] Use AsyncFn instead of Fn() -> Future in GPUI spawn methods
- [x] Implement it in the whole app
- [x] Implement it in the debugger 
- [x] Glance at the RPC crate, and see if those box future methods can
be switched over. Answer: It can't directly, as you can't make an
AsyncFn* into a trait object. There's ways around that, but they're all
more complex than just keeping the code as is.
- [ ] Fix platform specific code

Release Notes:

- N/A

crates/remote_server/src/unix.rs

@@ -272,7 +272,7 @@ fn start_server(
     })
     .detach();
 
-    cx.spawn(|cx| async move {
+    cx.spawn(async move |cx| {
         let mut stdin_incoming = listeners.stdin.incoming();
         let mut stdout_incoming = listeners.stdout.incoming();
         let mut stderr_incoming = listeners.stderr.incoming();
@@ -827,7 +827,7 @@ pub fn handle_settings_file_changes(
             .set_server_settings(&server_settings_content, cx)
             .log_err();
     });
-    cx.spawn(move |cx| async move {
+    cx.spawn(async move |cx| {
         while let Some(server_settings_content) = server_settings_file.next().await {
             let result = cx.update_global(|store: &mut SettingsStore, cx| {
                 let result = store.set_server_settings(&server_settings_content, cx);