title: Changing page title as it appears in MediaWiki category
body: <p>I've been trying to use DEFAULTSORT to sort pages based on a template parameter instead of the page title. This is how it appears at the top of the template:</p>
  
  <pre><code>{{DEFAULTSORT:{{{Username}}}}}
  </code></pre>
  
  <p>This is how it appears after the argument is transcluded:</p>
  
  <pre><code>{{DEFAULTSORT:d3xus}}
  </code></pre>
  
  <p>It would be nice for it to appear in categories as d3xus and not D3xus. There's no change in how the page is sorted because they both begin with the same symbol. Using an extension or magic word, is it possible to change how a page appears when viewed in a category? DEFAULTSORT only changes how the page is sorted with respect to other pages in the same category, but it does not change the page title in the category. </p>