Changed the link to point to the new location of the search engine.

mailing-lists.html

@@ -38,7 +38,7 @@
     <ul>
       <li>
 	<a
-	href="http://sane.informatik.uni-freiburg.de/htdig/search.html">Search
+	href="/htdig/">Search
 	the mailing list archives</a>.  Thanks to <a href="mailto:Jochen
 	Eisinger <jochen.eisinger@gmx.de>">Jochen Eisinger</A> for making
 	available the search engine.