[trivial] $LI() must wrap entire list item to generate valid HTML

It was outputting something like:

    <ol>
      <li>...</li>
      <p>...</p> <!-- p can not be a child of ol -->
      <li>...</li>
      <p>...</p> <!-- p can not be a child of ol -->
    </ol>

Which is invalid (though browsers managed to cope with the error visually).