Add Since: to gdk_x11_device_get_id(), gdk_x11_device_manager_lookup(), gdk_x11_window_set_utf8_property() docs

https://bugzilla.gnome.org/show_bug.cgi?id=667730

gdk/x11/gdkdevicemanager-x11.c

@@ -100,6 +100,8 @@ _gdk_x11_device_manager_new (GdkDisplay *display)
  *
  * Returns: (transfer none): (allow-none): The #GdkDevice wrapping the device ID,
  *          or %NULL if the given ID doesn't currently represent a device.
+ *
+ * Since: 3.2
  **/
 GdkDevice *
 gdk_x11_device_manager_lookup (GdkDeviceManager *device_manager,
@@ -145,6 +147,8 @@ gdk_x11_device_manager_lookup (GdkDeviceManager *device_manager,
  * </note>
  *
  * Returns: the XInput2 device ID.
+ *
+ * Since: 3.2
  **/
 gint
 gdk_x11_device_get_id (GdkDevice *device)

gdk/x11/gdkwindow-x11.c

@@ -3095,6 +3095,8 @@ gdk_x11_window_set_user_time (GdkWindow *window,
  * This function modifies or removes an arbitrary X11 window
  * property of type UTF8_STRING.  If the given @window is
  * not a toplevel window, it is ignored.
+ *
+ * Since: 3.4
  */
 void
 gdk_x11_window_set_utf8_property  (GdkWindow *window,