fix destroynotify() docs

References: https://gitlab.freedesktop.org/wlroots/wlroots/-/merge_requests/4421

dwl.c

@@ -1122,7 +1122,7 @@ destroylocksurface(struct wl_listener *listener, void *data)
 void
 destroynotify(struct wl_listener *listener, void *data)
 {
-	/* Called when the surface is destroyed and should never be shown again. */
+	/* Called when the xdg_toplevel is destroyed. */
 	Client *c = wl_container_of(listener, c, destroy);
 	wl_list_remove(&c->destroy.link);
 	wl_list_remove(&c->set_title.link);