Mention possible run options in the task modal placeholder (#8449)

Release Notes:

- Improved run task modal's placeholder

---------

Co-authored-by: Piotr Osiewicz <24362066+osiewicz@users.noreply.github.com>

crates/gpui/src/window.rs

@@ -1124,6 +1124,22 @@ impl<'a> WindowContext<'a> {
         false
     }
 
+    /// Represent this action as a key binding string, to display in the UI.
+    pub fn keystroke_text_for(&self, action: &dyn Action) -> String {
+        self.bindings_for_action(action)
+            .into_iter()
+            .next()
+            .map(|binding| {
+                binding
+                    .keystrokes()
+                    .iter()
+                    .map(ToString::to_string)
+                    .collect::<Vec<_>>()
+                    .join(" ")
+            })
+            .unwrap_or_else(|| action.name().to_string())
+    }
+
     /// Dispatch a mouse or keyboard event on the window.
     #[profiling::function]
     pub fn dispatch_event(&mut self, event: PlatformInput) -> bool {