www: Change de-AT to de

www/clients.php

@@ -107,7 +107,7 @@ if ($path == '') {
         header('Content-Type: application/xhtml+xml; charset=UTF-8');
         echo "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
         ?>
-<html xmlns="http://www.w3.org/1999/xhtml" lang="de-AT">
+<html xmlns="http://www.w3.org/1999/xhtml" lang="de">
 <head>
   <meta charset="UTF-8"/>
   <title>Mandanten - Elwig</title>