lib/rdoc/generator/template/darkfish/_sidebar_parent.rhtml
<%- if klass.type == 'class' then %>
<div id="parent-class-section" class="nav-section">
<h3>Parent</h3>
<%- if klass.superclass and not String === klass.superclass then -%>
<p class="link"><a href="<%= klass.aref_to klass.superclass.path %>"><%= klass.superclass.full_name %></a>
<%- else -%>
<p class="link"><%= klass.superclass %>
<%- end -%>
</div>
<%- end -%>