title: How to include excerpt option on taxonomy category page?
body: <p>I am trying to add an excerpt option to my category page, to display instead of my description.</p>
  
  <p>So basically, I need a box on this screen which will be able to be used as preview text.</p>
  
  <p>The code used to create this taxonomy is:</p>
  
  <pre><code>add_action( 'init', 'create_product_cat_external' );
  
  function create_product_cat_external() {
    register_taxonomy(
      'ExternalProducts',
      'products',
      array(
          'label' =&gt; __( 'External Products' ),
          'rewrite' =&gt; array( 'slug' =&gt; 'externalproducts' ),
          'hierarchical' =&gt; true,
      )
    );
  }
  </code></pre>
  
  <p>and the box needs to be here:</p>
  
  <p><img src="https://i.stack.imgur.com/U87A2.png" alt="screenshot of the UI"></p>