[gtk+] gtk_widget_intersect: fix annotations

[Christoph Reiter <creiter src gnome org>]

commit e4b0bedb5da263d5d6c9050bb1c2416e1d1a62f5
Author: Christoph Reiter <reiter christoph gmail com>
Date:   Thu Mar 30 10:45:00 2017 +0200

    gtk_widget_intersect: fix annotations
    
    https://bugzilla.gnome.org/show_bug.cgi?id=773228

 gtk/gtkwidget.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 4b00503..33547f1 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -7062,7 +7062,8 @@ gtk_widget_activate (GtkWidget *widget)
  * gtk_widget_intersect:
  * @widget: a #GtkWidget
  * @area: a rectangle
- * @intersection: (nullable): rectangle to store intersection of @widget and @area
+ * @intersection: (out caller-allocates) (optional): rectangle to store
+ *   intersection of @widget and @area
  *
  * Computes the intersection of a @widget’s area and @area, storing
  * the intersection in @intersection, and returns %TRUE if there was