Add "code_actions_on_format" (#7860)

This lets Go programmers configure `"code_actions_on_format": {
  "source.organizeImports": true,
}` so that they don't have to manage their imports manually

I landed on `code_actions_on_format` instead of `code_actions_on_save`
(the
VSCode version of this) because I want to run these when I explicitly
format
(and not if `format_on_save` is disabled).

Co-Authored-By: Thorsten <thorsten@zed.dev>

Release Notes:

- Added `"code_actions_on_format"` to control additional formatting
steps on format/save
([#5232](https://github.com/zed-industries/zed/issues/5232)).
- Added a `"code_actions_on_format"` of `"source.organizeImports"` for
Go ([#4886](https://github.com/zed-industries/zed/issues/4886)).

Co-authored-by: Thorsten <thorsten@zed.dev>

crates/editor/src/items.rs

@@ -704,10 +704,12 @@ impl Item for Editor {
 
     fn save(&mut self, project: Model<Project>, cx: &mut ViewContext<Self>) -> Task<Result<()>> {
         self.report_editor_event("save", None, cx);
-        let format = self.perform_format(project.clone(), FormatTrigger::Save, cx);
         let buffers = self.buffer().clone().read(cx).all_buffers();
-        cx.spawn(|_, mut cx| async move {
-            format.await?;
+        cx.spawn(|this, mut cx| async move {
+            this.update(&mut cx, |this, cx| {
+                this.perform_format(project.clone(), FormatTrigger::Save, cx)
+            })?
+            .await?;
 
             if buffers.len() == 1 {
                 project