[gtk+] GtkApplicationWindow: the help_overlay is nullable

[Timm Bäder <baedert src gnome org>]

commit d6cbe7ed2bffff42abe058564dc682fb38a23c74
Author: Timm Bäder <mail baedert org>
Date:   Sat Nov 14 22:56:01 2015 +0100

    GtkApplicationWindow: the help_overlay is nullable

 gtk/gtkapplicationwindow.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkapplicationwindow.c b/gtk/gtkapplicationwindow.c
index 7174edc..41cbee9 100644
--- a/gtk/gtkapplicationwindow.c
+++ b/gtk/gtkapplicationwindow.c
@@ -976,7 +976,7 @@ show_help_overlay (GSimpleAction *action,
 /**
  * gtk_application_window_set_help_overlay:
  * @window: a #GtkApplicationWindow
- * @help_overlay: a #GtkShortcutsWindow
+ * @help_overlay: (nullable): a #GtkShortcutsWindow
  *
  * Associates a shortcuts window with the application window, and
  * sets up an action with the name win.show-help-overlay to present