Add annotations

The goi scanner warns about these nowadays.
(cherry picked from commit 6aa8941b84)

gdk/gdkdnd.c

@@ -83,7 +83,7 @@ gdk_drag_get_protocol (GdkNativeWindow  xid,
  *
  * Retrieves the list of targets of the context.
  *
- * Return value: a #GList of targets
+ * Return value: (transfer none) (element-type GdkAtom): a #GList of targets
  *
  * Since: 2.22
  **/

gdk/gdkvisual.c

@@ -37,7 +37,8 @@
  *
  * Call g_list_free() on the return value when you're finished with it.
  * 
- * Return value: a list of visuals; the list must be freed, but not its contents
+ * Return value: (transfer container) (element-type GdkVisual):
+ *     a list of visuals; the list must be freed, but not its contents
  **/
 GList*
 gdk_list_visuals (void)

gdk/gdkwindow.c

@@ -2461,7 +2461,8 @@ gdk_window_get_effective_toplevel (GdkWindow *window)
  * The returned list must be freed, but the elements in the
  * list need not be.
  *
- * Return value: list of child windows inside @window
+ * Return value: (transfer container) (element-type GdkWindow):
+ *     list of child windows inside @window
  **/
 GList*
 gdk_window_get_children (GdkWindow *window)
@@ -2481,7 +2482,8 @@ gdk_window_get_children (GdkWindow *window)
  * Like gdk_window_get_children(), but does not copy the list of
  * children, so the list does not need to be freed.
  *
- * Return value: a reference to the list of child windows in @window
+ * Return value: (transfer none) (element-type GdkWindow):
+ *     a reference to the list of child windows in @window
  **/
 GList *
 gdk_window_peek_children (GdkWindow *window)
@@ -2610,7 +2612,8 @@ gdk_window_remove_filter (GdkWindow     *window,
  * The returned list should be freed with g_list_free(), but
  * its elements need not be freed.
  *
- * Return value: list of toplevel windows, free with g_list_free()
+ * Return value: (transfer container) (element-type GdkWindow):
+ *     list of toplevel windows, free with g_list_free()
  *
  * Since: 2.2
  **/

gdk/x11/gdkdnd-x11.c

@@ -3123,7 +3123,8 @@ gdk_drag_do_leave (GdkDragContext *context, guint32 time)
 /**
  * gdk_drag_begin:
  * @window: the source window for this drag.
- * @targets: the offered targets, as list of #GdkAtom<!-- -->s
+ * @targets: (transfer none) (element-type GdkAtom): the offered targets,
+ *     as list of #GdkAtom<!-- -->s
  * 
  * Starts a drag and creates a new drag context for it.
  *

gdk/x11/gdkinput.c

@@ -143,7 +143,7 @@ gdk_device_dispose (GObject *object)
  * Returns the list of available input devices for the default display.
  * The list is statically allocated and should not be freed.
  *
- * Return value: a list of #GdkDevice
+ * Return value: (transfer none) (element-type GdkDevice): a list of #GdkDevice
  **/
 GList *
 gdk_devices_list (void)

gdk/x11/gdkscreen-x11.c

@@ -1382,7 +1382,8 @@ gdk_screen_get_active_window (GdkScreen *screen)
  * windows it contains, so it should be freed using g_list_free() and
  * its windows unrefed using g_object_unref() when no longer needed.
  *
- * Return value: a list of #GdkWindow<!-- -->s for the current window stack,
+ * Return value: (transfer full) (element-type GdkWindow):
+ *     a list of #GdkWindow<!-- -->s for the current window stack,
  *               or %NULL.
  *
  * Since: 2.10

gdk/x11/gdkvisual-x11.c

@@ -521,8 +521,8 @@ gdk_query_visual_types (GdkVisualType **visual_types,
  *
  * Call g_list_free() on the return value when you're finished with it.
  * 
- * Return value: a list of visuals; the list must be freed, but not its 
- * contents
+ * Return value: (transfer container) (element-type GdkVisual):
+ *     a list of visuals; the list must be freed, but not its contents
  *
  * Since: 2.2
  **/

gdk/x11/gdkwindow-x11.c

@@ -3707,7 +3707,8 @@ gdk_x11_window_set_user_time (GdkWindow *window,
 /**
  * gdk_window_set_icon_list:
  * @window: The #GdkWindow toplevel window to set the icon of.
- * @pixbufs: A list of pixbufs, of different sizes.
+ * @pixbufs: (transfer none) (element-type GdkPixbuf):
+ *     A list of pixbufs, of different sizes.
  *
  * Sets a list of icons for the window. One of these will be used
  * to represent the window when it has been iconified. The icon is