Update questionhelper.rst

Author: SpacePossum

components/console/helpers/questionhelper.rst

@@ -212,14 +212,15 @@ convenient for passwords::
     On Windows systems, this ``stty`` command may generate gibberish output and
     mangle the input text. If that's your case, disable it with this command::
 
+        use Symfony\Component\Console\Helper\QuestionHelper;
         use Symfony\Component\Console\Question\ChoiceQuestion;
 
         // ...
         public function execute(InputInterface $input, OutputInterface $output)
         {
             // ...
             $helper = $this->getHelper('question');
-            $helper->disableStty();
+            QuestionHelper::disableStty();
 
             // ...
         }