Re-entrant SendKeystrokes (#20277)

Release Notes:

- Improved `workspace::SendKeystrokes` to support re-binding keys. For
example you can now do: `"x": ["workspace::SendKeystrokes", "\" _ x"]`
in vim mode to ensure that `x` does not clobber your clipboard.
- Improved key binding documentation

crates/workspace/src/workspace.rs

@@ -752,7 +752,7 @@ pub struct Workspace {
     leader_updates_tx: mpsc::UnboundedSender<(PeerId, proto::UpdateFollowers)>,
     database_id: Option<WorkspaceId>,
     app_state: Arc<AppState>,
-    dispatching_keystrokes: Rc<RefCell<Vec<Keystroke>>>,
+    dispatching_keystrokes: Rc<RefCell<(HashSet<String>, Vec<Keystroke>)>>,
     _subscriptions: Vec<Subscription>,
     _apply_leader_updates: Task<Result<()>>,
     _observe_current_user: Task<Result<()>>,
@@ -1784,6 +1784,11 @@ impl Workspace {
     }
 
     fn send_keystrokes(&mut self, action: &SendKeystrokes, cx: &mut ViewContext<Self>) {
+        let mut state = self.dispatching_keystrokes.borrow_mut();
+        if !state.0.insert(action.0.clone()) {
+            cx.propagate();
+            return;
+        }
         let mut keystrokes: Vec<Keystroke> = action
             .0
             .split(' ')
@@ -1791,16 +1796,16 @@ impl Workspace {
             .collect();
         keystrokes.reverse();
 
-        self.dispatching_keystrokes
-            .borrow_mut()
-            .append(&mut keystrokes);
+        state.1.append(&mut keystrokes);
+        drop(state);
 
         let keystrokes = self.dispatching_keystrokes.clone();
         cx.window_context()
             .spawn(|mut cx| async move {
                 // limit to 100 keystrokes to avoid infinite recursion.
                 for _ in 0..100 {
-                    let Some(keystroke) = keystrokes.borrow_mut().pop() else {
+                    let Some(keystroke) = keystrokes.borrow_mut().1.pop() else {
+                        keystrokes.borrow_mut().0.clear();
                         return Ok(());
                     };
                     cx.update(|cx| {
@@ -1817,7 +1822,8 @@ impl Workspace {
                         }
                     })?;
                 }
-                keystrokes.borrow_mut().clear();
+
+                *keystrokes.borrow_mut() = Default::default();
                 Err(anyhow!("over 100 keystrokes passed to send_keystrokes"))
             })
             .detach_and_log_err(cx);