[gtk+] Document gtk_sidebar_get_stack

[Matthias Clasen <matthiasc src gnome org>]

commit e14c0bb394473f8bbdb7c14f5065c58b9c0d2630
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Oct 22 00:36:16 2014 -0400

    Document gtk_sidebar_get_stack

 gtk/gtksidebar.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtksidebar.c b/gtk/gtksidebar.c
index 7ccc521..e5121ed 100644
--- a/gtk/gtksidebar.c
+++ b/gtk/gtksidebar.c
@@ -511,7 +511,11 @@ gtk_sidebar_set_stack (GtkSidebar *sidebar,
  * gtk_sidebar_get_stack:
  * @sidebar: a #GtkSidebar
  *
- * Returns: (transfer full): the associated #GtkStack
+ * Retrieves the stack.
+ * See gtk_sidebar_set_stack().
+ *
+ * Returns: (transfer full): the associated #GtkStack or
+ *     %NULL if none has been set explicitly
  *
  * Since: 3.16
  */