title: WooCommerce - add description before woocommerce_form_field() on checkout
body: <p>I'm adding some custom fields to my checkout page, with following code:</p>
  
  <pre><code>add_action( 'woocommerce_before_order_notes', 'bs_custom_checkout_fields' );
  function bs_custom_checkout_fields( $checkout ) {
  
      woocommerce_form_field( 'order_domain_name', array(
          'type'          =&gt; 'text',
          'class'         =&gt; array('my-field-class form-row-wide'),
          'label'         =&gt; __('Name','bs'),
          'placeholder'   =&gt; __('Enter the name','bs'),
          'required'      =&gt; true,
      ), $checkout-&gt;get_value( 'order_domain_name' ));
  }
  </code></pre>
  
  <p>I would need to add some additional description before this field, to explain the user what this field means. Is there way to do that?</p>
  
  <p>Thanks</p>