[gtk/bilelmoussaoui/g-i] gtk: mark gtk_icon_view_create_drag_icon as nullable

[Bilal Elmoussaoui <bilelmoussaoui src gnome org>]

commit 06570443b79f0bc664e2bfbae6093ae8088b327a
Author: Bilal Elmoussaoui <bil elmoussaoui gmail com>
Date:   Sat Jan 1 18:33:29 2022 +0100

    gtk: mark gtk_icon_view_create_drag_icon as nullable

 gtk/gtkiconview.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkiconview.c b/gtk/gtkiconview.c
index 55829feac4..a01879afa8 100644
--- a/gtk/gtkiconview.c
+++ b/gtk/gtkiconview.c
@@ -6519,7 +6519,7 @@ gtk_icon_view_get_dest_item_at_pos (GtkIconView              *icon_view,
  * Creates a `GdkPaintable` representation of the item at @path.
  * This image is used for a drag icon.
  *
- * Returns: (transfer full): a newly-allocated `GdkPaintable` of the drag icon.
+ * Returns: (transfer full) (nullable): a newly-allocated `GdkPaintable` of the drag icon.
  **/
 GdkPaintable *
 gtk_icon_view_create_drag_icon (GtkIconView *icon_view,