title: Use field label as placeholder with django-widget-tweaks
body: <p>I am using django-widget-tweaks and unable to figure out <em>how to add a field variable as placeholder</em>, like the following:</p>
  
  <pre><code>&lt;div class="col-sm-10"&gt;
   {{ field|append_attr:"class:form-control"|append_attr:"placeholder:field.label" }}
   {% if field.help_text %}
     &lt;p class="help-block"&gt;&lt;small&gt;{{ field.help_text }}&lt;/small&gt;&lt;/p&gt;
   {% endif %}
  &lt;/div&gt;
  </code></pre>
  
  <p><code>field.label</code> above does not evaluate and puts the string <code>"field.label"</code> as the placeholder on the page.</p>
  
  <p>Some SO posts suggest registering a custom tag/filter which seems complicated for something this simple.</p>