Fixed code examples in book/translation

Author: wouterj

book/translation.rst

@@ -888,6 +888,7 @@ empty, add the following:
 
         // src/Acme/BlogBundle/Entity/Author.php
 
+        // ...
         use Symfony\Component\Validator\Mapping\ClassMetadata;
         use Symfony\Component\Validator\Constraints\NotBlank;