Fix E_STRICT warning in i18n example.

examples/i18n/I18n.php

@@ -14,7 +14,7 @@ class I18n {
         'My name is {{ name }}.' => 'Me llamo {{ name }}.',
     );
 
-    public function __trans($text) {
+    public static function __trans($text) {
         return isset(self::$dictionary[$text]) ? self::$dictionary[$text] : $text;
     }
 }