[mutter] clutter: Make docs match with signal description

[Carlos Garnacho <carlosg src gnome org>]

commit bf12a2497be3a3c61f9f54c6ea9b45fee02ba8d5
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Feb 25 19:56:56 2019 +0100

    clutter: Make docs match with signal description
    
    Makes gobject-introspection happy again.
    
    Pointed out by Robert Mader at:
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/196

 clutter/clutter/clutter-actor.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/clutter/clutter/clutter-actor.c b/clutter/clutter/clutter-actor.c
index 5caa39374..100b80459 100644
--- a/clutter/clutter/clutter-actor.c
+++ b/clutter/clutter/clutter-actor.c
@@ -8014,6 +8014,7 @@ clutter_actor_class_init (ClutterActorClass *klass)
    * ClutterActor::queue-redraw:
    * @actor: the actor we're bubbling the redraw request through
    * @origin: the actor which initiated the redraw request
+   * @volume: paint volume to redraw
    *
    * The ::queue_redraw signal is emitted when clutter_actor_queue_redraw()
    * is called on @origin.