Update irc links

The xiph.org channels have moved to the new network. Update IRC links to match. Replace the native webchat link with kiwiirc.

doc/index.html

@@ -192,7 +192,7 @@ browser.</p>
 <ul>
 <li>The <a href="http://lists.xiph.org/mailman/listinfo/icecast">Icecast Mailing list</a></li>
 <li>The <a href="http://lists.xiph.org/mailman/listinfo/icecast-dev">Icecast Developer Mailing list</a>, for more development-related questions.</li>
-<li>Icecast IRC Chat at the <a href="irc://irc.freenode.net:6667/#icecast">#icecast</a> channel on irc.freenode.net</li>
+<li>Icecast IRC Chat at the <a href="ircs://irc.libera.chat:6697/#icecast">#icecast</a> channel on libera.chat</li>
 </ul>
               
             </div>