Debounce refresh of inlay hints on buffer edits (#8282)

I think this makes it less chaotic to edit text when the inlay hints are
on.

It's for cases where you're editing to the right side of an inlay hint.
Example:

```rust
for name in names.iter().map(|item| item.len()) {
    println!("{:?}", name);
}
```

We display a `usize` inlay hint right next to `name`.

But as soon as you remove that `.` in `names.iter` your cursor jumps
around because the inlay hint has been removed.

With this change we now have a 700ms debounce before we update the inlay
hints.

VS Code seems to have an even longer debounce, I think somewhere around
~1s.

Release Notes:

- Added debouncing to make it easier to edit text when inlay hints are
enabled and to save rendering of inlay hints when scrolling. Both
debounce durations can be configured with `{"inlay_hints":
{"edit_debounce_ms": 700}}` (default) and `{"inlay_hints":
{"scroll_debounce_ms": 50}}`. Set a value to `0` to turn off the
debouncing.


### Before


https://github.com/zed-industries/zed/assets/1185253/3afbe548-dcfb-45a3-ab9f-cce14c04a148



### After



https://github.com/zed-industries/zed/assets/1185253/7ea90e42-bca6-4f6c-995e-83324669ab43

---------

Co-authored-by: Kirill <kirill@zed.dev>

crates/editor/src/editor.rs

@@ -1360,6 +1360,7 @@ enum InlayHintRefreshReason {
     RefreshRequested,
     ExcerptsRemoved(Vec<ExcerptId>),
 }
+
 impl InlayHintRefreshReason {
     fn description(&self) -> &'static str {
         match self {
@@ -3029,6 +3030,12 @@ impl Editor {
         }
 
         let reason_description = reason.description();
+        let ignore_debounce = matches!(
+            reason,
+            InlayHintRefreshReason::SettingsChange(_)
+                | InlayHintRefreshReason::Toggle(_)
+                | InlayHintRefreshReason::ExcerptsRemoved(_)
+        );
         let (invalidate_cache, required_languages) = match reason {
             InlayHintRefreshReason::Toggle(enabled) => {
                 self.inlay_hint_cache.enabled = enabled;
@@ -3091,6 +3098,7 @@ impl Editor {
             reason_description,
             self.excerpts_for_inlay_hints_query(required_languages.as_ref(), cx),
             invalidate_cache,
+            ignore_debounce,
             cx,
         ) {
             self.splice_inlay_hints(to_remove, to_insert, cx);