Fixed canonical ASPN C++-sig URL

[SVN r29631]

more/mailing_lists.htm

@@ -176,7 +176,7 @@ postings. Subscribe or unsubscribe at the <a href="http://lists.boost.org/mailma
         access</a> and <a href="http://news.gmane.org/thread.php?group=gmane.comp.python.c%2b%2b"        >Searchable
         Archives</a> as well. Please see <a href="#gmane_post">this note</a>
         before posting to the newsgroup. There are also searchable archives
-        at <a href="http://aspn.activestate.com/ASPN/Mail/Browse/Threaded/c++-sig"        >ASPN</a>.
+        at <a href="http://aspn.activestate.com/ASPN/Mail/Browse/Threaded/cpp-sig"        >ASPN</a>.
         
 
         <h3><a name="langbinding">Language Binding</a></h3>