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>

assets/settings/default.json

@@ -482,6 +482,7 @@
   "deno": {
     "enable": false
   },
+  "code_actions_on_format": {},
   // Different settings for specific languages.
   "languages": {
     "Plain Text": {
@@ -492,7 +493,10 @@
     },
     "Go": {
       "tab_size": 4,
-      "hard_tabs": true
+      "hard_tabs": true,
+      "code_actions_on_format": {
+        "source.organizeImports": true
+      }
     },
     "Markdown": {
       "soft_wrap": "preferred_line_length"