refactor check for language file

Author: mambax7

include/issues.php

@@ -30,11 +30,7 @@
 
 $moduleDirName = \basename(\dirname(__DIR__));
 
-if (isset($GLOBALS['xoopsConfig']['language']) && file_exists(dirname(__DIR__) . '/language/' . $GLOBALS['xoopsConfig']['language'] . '/admin.php')) {
-    include_once dirname(__DIR__) . '/language/' . $GLOBALS['xoopsConfig']['language'] . '/admin.php';
-} else {
-    include_once dirname(__DIR__) . '/language/english/admin.php'; // messages will be in english
-}
+xoops_loadLanguage('admin', $moduleDirName);
 
 //session_start();