Display the first keystroke instead of an error for multi-keystroke binding (#31456)

Ideally we would show multi-keystroke binding, but I'd say this improves
over the status quo.

A partial solution to #27334

Release Notes:

- Fixed spurious warning for lack of edit prediction on multi-keystroke
binding

Co-authored-by: Ben Kunkle <ben@zed.dev>

crates/editor/src/editor.rs

@@ -2261,6 +2261,8 @@ impl Editor {
             window.bindings_for_action_in_context(&AcceptEditPrediction, key_context)
         };
 
+        // TODO: if the binding contains multiple keystrokes, display all of them, not
+        // just the first one.
         AcceptEditPredictionBinding(bindings.into_iter().rev().find(|binding| {
             !in_conflict
                 || binding

crates/editor/src/element.rs

@@ -6666,7 +6666,7 @@ impl AcceptEditPredictionBinding {
     pub fn keystroke(&self) -> Option<&Keystroke> {
         if let Some(binding) = self.0.as_ref() {
             match &binding.keystrokes() {
-                [keystroke] => Some(keystroke),
+                [keystroke, ..] => Some(keystroke),
                 _ => None,
             }
         } else {