Minor string change: Tomboy (add a colon character)

["Boyd Timothy" <btimothy gmail com>]

boyd bht-tp:~/projects/tomboy> svn diff Tomboy/PreferencesDialog.cs
Index: Tomboy/PreferencesDialog.cs
===================================================================
--- Tomboy/PreferencesDialog.cs (revision 1311)
+++ Tomboy/PreferencesDialog.cs (working copy)
@@ -760,7 +760,7 @@
                       if (info.Dependencies.Count > 0) {
                               sb.Append (string.Format (
                                       "<b>{0}</b>\n",
-                                       Catalog.GetString ("Add-in
Dependencies")));
+                                       Catalog.GetString ("Add-in
Dependencies:")));
                               foreach
(Mono.Addins.Description.Dependency dep in info.Dependencies) {
                                       sb.Append (dep.Name + "\n");
                               }