title: Field position limit in Sphinx to *start* search at character position?
body: <p>As far as I can tell "Field position limit" in sphinx only allows you to force search to the first N characters in a document? Is there anyway to use it to force search AFTER the first N characters instead?</p>
  
  <pre><code>The quick brown fox jumped over the lazy dog and he was crazy as a fox and just as fast
  </code></pre>
  
  <ul>
  <li>Fox[20]</li>
  </ul>
  
  <p>will find the first fox and not the second.</p>
  
  <p>What I am looking for is something like </p>
  
  <ul>
  <li>Fox[50] that won't start search until char 50 ("and he was crazy as a fox and just as fast")</li>
  </ul>