shell/window-preview-layout: Mark return value as nullable

The function may return null, so we should mark it as such, even
if that information is currently unused.

https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/6351

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2622>

diff --git a/src/shell-window-preview-layout.c b/src/shell-window-preview-layout.c
index 062726409343a8f08cb09c524434b23d77cd488c..9cf6633b19b99bd4caf551c763e5ecdc7f3d0848 100644 (file)
--- a/src/shell-window-preview-layout.c
+++ b/src/shell-window-preview-layout.c
@@ -354,7 +354,7 @@ shell_window_preview_layout_class_init (ShellWindowPreviewLayoutClass *klass)
  * to the container. If @window is already part of the preview, this
  * function will do nothing.
  *
- * Returns: (transfer none): The newly created actor drawing @window
+ * Returns: (nullable) (transfer none): The newly created actor drawing @window
  */
 ClutterActor *
 shell_window_preview_layout_add_window (ShellWindowPreviewLayout *self,