Description classes missing in the "before" part in form-element.twig

Problem/Motivation

In the form-element.twig template the description_classes are not being added in the 'before' case as in the 'after' case:

    {% if description_display == 'before' and description.content %}
      <div{{description.attributes}}>
        {{ description.content }}
      </div>

Whereas in the 'after' case we have the following:

  {% if description_display in ['after', 'invisible'] and description.content %}
    <small{{description.attributes.addClass(description_classes)}}>
      {{ description.content }}
    </small>

Proposed resolution

Change the 'before' (line 89) to add the same classes as the in 'after' (line 115).