3628 Sub tag trees not properly nested

The markup for lists in the sub tag section of tag pages (e.g. /tags/Alternate%20Universe) was wrong. http://code.google.com/p/otwarchive/issues/detail?id=3628

Old and wrong:
```
<ul>
  <li>Thing 1</li>
  <ul>
    <li>Thing 1's Sub Thing 1</li>
  </ul>
  <li>Thing 2</li>
</ul>
```

New and not wrong:
```
<ul>
  <li>Thing 1
    <ul>
      <li>Thing 1's Sub Thing 1</li>
    </ul>
  </li>
  <li>Thing 2</li>
</ul>
```