[gtk/bilelmoussaoui/g-i] gtk: add nullable annotations to PopoverMenuBar

[Bilal Elmoussaoui <bilelmoussaoui src gnome org>]

commit 41eb6e79fb22e58cde67a48531c20abbd5edbad5
Author: Bilal Elmoussaoui <bil elmoussaoui gmail com>
Date:   Sat Jan 1 17:45:08 2022 +0100

    gtk: add nullable annotations to PopoverMenuBar
    
    The constructor/setter accepts a null as a model so should the getter

 gtk/gtkpopovermenubar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkpopovermenubar.c b/gtk/gtkpopovermenubar.c
index b2a3635e5a..a3fbd8fb09 100644
--- a/gtk/gtkpopovermenubar.c
+++ b/gtk/gtkpopovermenubar.c
@@ -746,7 +746,7 @@ gtk_popover_menu_bar_set_menu_model (GtkPopoverMenuBar *bar,
  *
  * Returns the model from which the contents of @bar are taken.
  *
- * Returns: (transfer none): a `GMenuModel`
+ * Returns: (transfer none) (nullable): a `GMenuModel`
  */
 GMenuModel *
 gtk_popover_menu_bar_get_menu_model (GtkPopoverMenuBar *bar)