added missing DETAIL_STARTED event to lib/exe/detail.php

lib/exe/detail.php

@@ -2,6 +2,7 @@
 if(!defined('DOKU_INC')) define('DOKU_INC',dirname(__FILE__).'/../../');
 define('DOKU_MEDIADETAIL',1);
 require_once(DOKU_INC.'inc/init.php');
+trigger_event('DETAIL_STARTED', $tmp=array());
 //close session
 session_write_close();