Fixes #5775: Collapse labels/badges

* When :empty, display: none;
* Add documentation for change in behavior

docs/templates/pages/components.mustache

@@ -1788,6 +1788,9 @@
             </tbody>
           </table>
 
+          <h3>{{_i}}Easily collapsible{{/i}}</h3>
+          <p>{{_i}}For easy implementation, labels and badges will simply collapse (via CSS's <code>:empty</code> selector) when no content exists within.{{/i}}</p>
+
         </section>