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

[Bilal Elmoussaoui <bilelmoussaoui src gnome org>]

commit b803bb5edb1c079c676ad4a5b1ed009c4d950c45
Author: Bilal Elmoussaoui <bil elmoussaoui gmail com>
Date:   Sat Jan 1 18:04:24 2022 +0100

    gtk: mark MultiSelection::get_model as nullable
    
    the constructor & setter takes a nullable model

 gtk/gtkmultiselection.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkmultiselection.c b/gtk/gtkmultiselection.c
index 26590ec55f..bee83622c6 100644
--- a/gtk/gtkmultiselection.c
+++ b/gtk/gtkmultiselection.c
@@ -396,7 +396,7 @@ gtk_multi_selection_new (GListModel *model)
  *
  * Returns the underlying model of @self.
  *
- * Returns: (transfer none): the underlying model
+ * Returns: (transfer none) (nullable): the underlying model
  */
 GListModel *
 gtk_multi_selection_get_model (GtkMultiSelection *self)