[gtk+] Mention the de-facto standard filename extension

[Matthias Clasen <matthiasc src gnome org>]

commit ba1f2ae3fc9f23e6f260021dc53d77d39aa3f0fe
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Feb 11 00:57:39 2013 -0500

    Mention the de-facto standard filename extension
    
    GtkBuilder files are commonly named .ui - mention that in the
    docs.
    https://bugzilla.gnome.org/show_bug.cgi?id=590325

 gtk/gtkbuilder.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtkbuilder.c b/gtk/gtkbuilder.c
index 9923bc2..3d94605 100644
--- a/gtk/gtkbuilder.c
+++ b/gtk/gtkbuilder.c
@@ -59,7 +59,7 @@
  * or just <firstterm>UI definitions</firstterm> if the context is clear. Do not
  * confuse GtkBuilder UI Definitions with
  * <link linkend="XML-UI">GtkUIManager UI Definitions</link>, which are more
- * limited in scope.
+ * limited in scope. It is common to use <filename>.ui</filename> as the filename extension for files containing GtkBuilder UI definitions.
  * </para>
  * <programlisting>
  * <xi:include xmlns:xi="http://www.w3.org/2001/XInclude"; parse="text" href="../../../../gtk/gtkbuilder.rnc">