Update questionhelper.rst

hello,

when running the example as it is, a deprecation message is shown (i'm on PHP 8.1.6). the deprecation message says that ``trim(): Passing null to parameter #1 ($string) of type string is deprecated``.
what if we add a normalizer that returns an empty string when the entered value is `null` otherwise returns the user's intial input.  with this suggestion, the example works great

Author: issamkhadiri1989

components/console/helpers/questionhelper.rst

@@ -420,6 +420,9 @@ You can also use a validator with a hidden question::
         $helper = $this->getHelper('question');
 
         $question = new Question('Please enter your password');
+        $question->setNormalizer(function ($value) {
+            return null === $value ? '' : $value;
+        });
         $question->setValidator(function ($value) {
             if (trim($value) == '') {
                 throw new \Exception('The password cannot be empty');