docs: Fix example code in BindingPool

The code sample in the gtk-doc annotations for ClutterBindingPool shows
the arguments in the wrong order.

http://bugzilla.clutter-project.org/show_bug.cgi?id=2133

Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>

clutter/clutter-binding-pool.c

@@ -81,9 +81,10 @@
  *    * mask of the key event. the returned value can be directly
  *    * used to signal that the actor has handled the event.
  *    */
- *   return clutter_binding_pool_activate (pool, G_OBJECT (actor),
+ *   return clutter_binding_pool_activate (pool,
  *                                         key_event->keyval,
- *                                         key_event->modifier_state);
+ *                                         key_event->modifier_state,
+ *                                         G_OBJECT (actor));
  * ]|
  *
  * The clutter_binding_pool_activate() function will return %FALSE if