[clutter] Fix annotation for bind_model()

[Emmanuele Bassi <ebassi src gnome org>]

commit b47e1616eb1201eae35955aa62aebc352927c67b
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Wed Dec 9 12:44:20 2015 +0000

    Fix annotation for bind_model()
    
    The (optional) annotation should only be used for (out) arguments; in
    arguments that can be NULL should use the (nullable) annotation.

 clutter/clutter-actor.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/clutter/clutter-actor.c b/clutter/clutter-actor.c
index fb9f5c6..6298b1c 100644
--- a/clutter/clutter-actor.c
+++ b/clutter/clutter-actor.c
@@ -20834,7 +20834,7 @@ clutter_actor_child_model__items_changed (GListModel *model,
 /**
  * clutter_actor_bind_model:
  * @self: a #ClutterActor
- * @model: (optional): a #GListModel
+ * @model: (nullable): a #GListModel
  * @create_child_func: a function that creates #ClutterActor instances
  *   from the contents of the @model
  * @user_data: user data passed to @create_child_func