[gtk+] GtkDialog: Fix up docs

[Matthias Clasen <matthiasc src gnome org>]

commit 31ff1204a43de5acb617c4982e65421fba06f3c8
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Apr 26 11:54:02 2015 -0400

    GtkDialog: Fix up docs
    
    The ui fragment in the example was causing a critical
    warning, which is not nice. Fix it to work properly.

 gtk/gtkdialog.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkdialog.c b/gtk/gtkdialog.c
index b02c604..21e9004 100644
--- a/gtk/gtkdialog.c
+++ b/gtk/gtkdialog.c
@@ -160,7 +160,9 @@
  *     <object class="GtkButton" id="button_cancel"/>
  *   </child>
  *   <child type="action">
- *     <object class="GtkButton" id="button_ok"/>
+ *     <object class="GtkButton" id="button_ok">
+ *       <property name="can-default">True</property>
+ *     </object>
  *   </child>
  *   <action-widgets>
  *     <action-widget response="cancel">button_cancel</action-widget>