[gtk/wip/phako/fix-activate-action-annotation] widget: Mark format as nullable in activate_action

[Jens Georg <jensgeorg src gnome org>]

commit e600fcbcc52de7851fc9f320271879c55a9711fd
Author: Jens Georg <mail jensge org>
Date:   Tue Apr 19 10:17:39 2022 +0200

    widget: Mark format as nullable in activate_action
    
    The doc and the code allow it to be NULL

 gtk/gtkwidget.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index afe7e9224e..56e3fa25bf 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -11345,7 +11345,7 @@ gtk_widget_activate_action_variant (GtkWidget  *widget,
  * gtk_widget_activate_action:
  * @widget: a `GtkWidget`
  * @name: the name of the action to activate
- * @format_string: GVariant format string for arguments or %NULL
+ * @format_string: (nullable): GVariant format string for arguments or %NULL
  *   for no arguments
  * @...: arguments, as given by format string
  *