wlr_scene: Add 'struct' to comment in wlr_scene_create() to permit auto-linkify.

include/wlr/types/wlr_scene.h

@@ -307,8 +307,8 @@ struct wlr_scene_node *wlr_scene_node_at(struct wlr_scene_node *node,
 /**
  * Create a new scene-graph.
  *
- * The graph is also a wlr_scene_node. Associated resources can be destroyed
- * through wlr_scene_node_destroy().
+ * The graph is also a struct wlr_scene_node. Associated resources can be
+ * destroyed through wlr_scene_node_destroy().
  */
 struct wlr_scene *wlr_scene_create(void);