title: Interpolation doesn't work in pug value attribute
body: <p>I am trying to use the below markup to autopopulate the form.</p>
  
  <pre><code>textarea.form-control(rows='5',id='description' name='description', value='#{product.description}')
  </code></pre>
  
  <p>where product is the variable from js file.But the form doesn't autopopulate the values</p>
  
  <p>route:</p>
  
  <pre><code>router.get('/update/:id', function(req, res) {
    productApi.getProductById(req.params.id, function(err, product) {
  
      res.render('crud/update', {product: product});
    });
  });
  </code></pre>
  
  <p>json:</p>
  
  <pre><code>products: [
      {
        "id": 1,
        "description": "Tasty cookies"
      },
      {
        "id": 2,
        "description": "delicious candies"
      }]
  </code></pre>