title: Why does full-text search inside titles return error
body: <p>When I perform full-text search with Wikipedia API, I can not narrow it to titles only (srwhat=title).</p>
  
  <p>So while search anywhere (default) 
    <a href="http://en.wikipedia.org/w/api.php?action=query&amp;list=search&amp;srsearch=sql&amp;srnamespace=14&amp;format=xml" rel="nofollow">http://en.wikipedia.org/w/api.php?action=query&amp;list=search&amp;srsearch=sql&amp;srnamespace=14&amp;format=xml</a></p>
  
  <p>returns results, if I add srwhat=title, I got an error: </p>
  
  <pre><code>&lt;api servedby="mw69"&gt;
    &lt;error code="srsearch-title-disabled" info="title search is disabled"/&gt;
  &lt;/api&gt;
  </code></pre>
  
  <p>This error is even listed in the docs ( <a href="http://www.mediawiki.org/wiki/API:Search" rel="nofollow">http://www.mediawiki.org/wiki/API:Search</a> ), but without any explanation.</p>