bug #3840 Update dialoghelper.rst (jdecoster)

This PR was submitted for the 2.4 branch but it was merged into the 2.3 branch instead (closes #3840).

Discussion
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Update dialoghelper.rst

At the "Validating a Hidden Response" the example validation didn't respond anything so the $password var was NULL

Commits
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c1812a9 Update dialoghelper.rst
036d276 Update dialoghelper.rst

Author: weaverryan

components/console/helpers/dialoghelper.rst

@@ -156,9 +156,11 @@ You can also ask and validate a hidden response::
     $dialog = $this->getHelperSet()->get('dialog');
 
     $validator = function ($value) {
-        if (trim($value) == '') {
+        if ('' === trim($value)) {
             throw new \Exception('The password can not be empty');
         }
+        
+        return $value;
     };
 
     $password = $dialog->askHiddenResponseAndValidate(