title: wp_list_categories() add span to the category name
body: <p>I've tried a heap of "solutions" but non allow me add a simple </p>
  
  <pre><code>&lt;span&gt;&lt;/span&gt;
  </code></pre>
  
  <p>using functions.php /default-widgets.php
   to the category name, eg.</p>
  
  <pre><code>&lt;li&gt;&lt;a&gt;&lt;span&gt;&lt;/span&gt;Category 1&lt;/a&gt;&lt;/li&gt;
  </code></pre>
  
  <p>the closest I've come replaces the category post count using str_replace.
  I don't want to call the widget straight from the theme because it messes up the order or use jquery, is their a way of doing this "easily" or will WP not allow it.</p>
  
  <p>Thanks</p>