Add link to Components guide from @template box.

    def to_html(contents)

      <<-EOHTML

      <div class='signature-box template'>

      <p>This is a template method. A hook into the functionality of this class.

      <p>This is a <a href="#!/guide/components">template method</a>.

         a hook into the functionality of this class.

         Feel free to override it in child classes.</p>

      </div>

      EOHTML