Add html to WooCommerce category shortcode output
<p>How can I filter the output of the WooCommerce <code>'product categories'</code> shortcode. I need to add a button into each product in the loop.</p>

<p><a href="https://docs.woothemes.com/document/woocommerce-shortcodes/#section-13" rel="nofollow">Docs WooCommerce: Product Categories shortcode</a></p>

<p><a href="https://github.com/woothemes/woocommerce/blob/master/includes/class-wc-shortcodes.php" rel="nofollow">WooCommerce code source <em>(github)</em>: class-wc-shortcodes.php</a></p>

<p>It should work. The syntax is strange for me and I'm not sure about how I am supposed to change <code>{$product_categories}</code> syntax code in it:</p>

<pre><code>function add_html_to_shortcode_product_categories() {

  echo '&lt;a class = "cta_btn" href="#"&gt;shop now&lt;/a&gt;';

}

add_action('woocommerce_shortcode_after_{$product_categories}_loop', 'add_html_to_shortcode_product_categories', 20);
</code></pre>

<p>Some help would be greatly appreciated.</p>