title: pug doesn't iterate array of object
body: <p>i'm using <code>express-validator</code> and when i log my errors, everything is fine:</p>
  
  <pre><code> errors:
     [ { value: '',
         msg: 'Email Field is empty',
         param: 'email',
         location: 'body' },
       { value: '',
         msg: 'Your email is not valid',
         param: 'email',
         location: 'body' } ] }
  </code></pre>
  
  <p>in my <code>register.pug</code> view:</p>
  
  <pre><code>   if(errors)
        .alert.alert-danger
            ul.mb-0
               each error in errors
                  li=error.msg
  </code></pre>
  
  <p>this is my route:</p>
  
  <pre><code>router.post(
    "/register",
    [
      check("email")
        .notEmpty()
        .withMessage("Email Field is empty"),
      check("email")
        .isEmail()
        .withMessage("Your email is not valid")
    ],
    function(req, res) {
      const errors = validationResult(req);
      res.render("register", { errors });
    }
  );
  </code></pre>
  
  <p>this is output:
  <a href="https://i.stack.imgur.com/7ZfTQ.png" rel="nofollow noreferrer">output image</a></p>
  
  <p>it doesn't display error messages.
  can you help me?</p>