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/debugger_ui/src/session/running/console.rs

@@ -213,8 +213,8 @@ impl Render for Console {
     fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
         let session = self.session.clone();
         let token = self.last_token;
-        self.update_output_task = cx.spawn_in(window, move |this, mut cx| async move {
-            _ = session.update_in(&mut cx, move |session, window, cx| {
+        self.update_output_task = cx.spawn_in(window, async move |this, cx| {
+            _ = session.update_in(cx, move |session, window, cx| {
                 let (output, last_processed_token) = session.output(token);
 
                 _ = this.update(cx, |this, cx| {
@@ -342,7 +342,7 @@ impl ConsoleQueryBarCompletionProvider {
 
         let query = buffer.read(cx).text();
 
-        cx.spawn(|_, cx| async move {
+        cx.spawn(async move |_, cx| {
             let matches = fuzzy::match_strings(
                 &string_matches,
                 &query,