[pygtk] Add a note on the new property added in GTK+ 2.16

[Gian Mario Tagliaretti <gianmt src gnome org>]

commit 05081bbd93374d121e4b11e44e474fff6ff026b1
Author: Gian Mario Tagliaretti <gianmt gnome org>
Date:   Thu Aug 13 17:33:20 2009 +0200

    Add a note on the new property added in GTK+ 2.16

 docs/reference/pygtk-gtkactivatable.xml |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/docs/reference/pygtk-gtkactivatable.xml b/docs/reference/pygtk-gtkactivatable.xml
index 6518a6e..ed4b7fa 100644
--- a/docs/reference/pygtk-gtkactivatable.xml
+++ b/docs/reference/pygtk-gtkactivatable.xml
@@ -70,7 +70,7 @@
                                 Note: <link linkend="class-gtkactivatable"><classname>gtk.Activatable</classname></link>
                                 implementors need to handle the "related-action" property and call
                                 <methodname><link linkend="method-gtkactivatable--do-set-related-action">gtk.Activatable.do_set_related_action</link></methodname>()
-                                when it changes.
+                                when it changes. This property is available in GTK+ 2.16 and above.
                             </entry>
                         </row>
                         <row valign="top">