Fix broken reference to CommandCompletionTester class

Author: arogachev

console/input.rst

@@ -368,7 +368,7 @@ Testing the Completion script
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The Console component comes with a special
-:class:`Symfony\\Component\\Console\\Test\\CommandCompletionTester`` class
+:class:`Symfony\\Component\\Console\\Tester\\CommandCompletionTester.php`` class
 to help you unit test the completion logic::
 
     // ...