This widget renders each option as a link, intead of an actual <input>. It has
one method that you can overide for additional customizability.
option_string() should return a string with 3 Python keyword arugment
1. ``attrs``: This is a string with all the attributes that will be on the
final ``<a>`` tag.
2. ``query_string``: This is the query string for use in the ``href``
option on the ``<a>`` elemeent.
3. ``label``: This is the text to be displayed to the user.