presence: docs - remove extra section end tag

src/modules/presence/doc/presence_admin.xml

@@ -1285,7 +1285,6 @@ pres_update_watchers("sip:[email protected]", "presence");
 </programlisting>
     </section>
 
-<section>
 	<section id="presence.r.publish_cache_sync">
 	  <title>presence.publish_cache_sync</title>
 	  <para>