[gtk+] docs: Add missing transfer annotation to GtkBox

[Matthias Clasen <matthiasc src gnome org>]

commit ac5fbb5ef3183c4b5699fcb71102c1f040a66fcf
Author: Marcus Karlsson <mk acc umu se>
Date:   Sat Apr 12 20:22:15 2014 +0200

    docs: Add missing transfer annotation to GtkBox
    
    The gtk_box_get_center_widget function is missing a transfer annotation
    for the returned widget. No transfer is done, so set transfer to none.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=728093

 gtk/gtkbox.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkbox.c b/gtk/gtkbox.c
index 6b9391e..557d9fd 100644
--- a/gtk/gtkbox.c
+++ b/gtk/gtkbox.c
@@ -2614,7 +2614,7 @@ gtk_box_set_center_widget (GtkBox    *box,
  *
  * Retrieves the center widget of the box.
  *
- * Returns: the center widget
+ * Returns: (transfer none): the center widget
  *
  * Since: 3.12
  */