Add parameter summary to hostclass html docs

Format cribbed from YARD method and attribute summary blocks. Still some work
to do, but initial results don't look that bad.

lib/puppetx/yardoc/yard/templates/default/hostclass/html/parameter_details.erb

@@ -0,0 +1,18 @@
+<h2>Parameter Summary<small>(<a href="#" class="summary_toggle">collapse</a>)</small></h2>
+<ul class="summary">
+  <% object.parameters.each do |param| %>
+    <li>
+      <a href="#">
+        <span class="summary_signature">
+          -
+          <strong><%= h param[0] %></strong>
+          <% unless param[1].nil? %>
+            <%# TODO: Linkify defaults that resolve to variable declarations in a different scope. %>
+            => <%= h param[1] %>
+          <% end %>
+        </span>
+        <%# TODO: Grab onto @param tags and insert text/type. %>
+      </a>
+    </li>
+  <% end %>
+</ul>

lib/puppetx/yardoc/yard/templates/default/hostclass/setup.rb

@@ -1,7 +1,12 @@
 include T('default/module')
 
 def init
-  sections :header, :box_info, :pre_docstring, T('docstring'), :subclasses
+  sections :header, :box_info, :pre_docstring, T('docstring'), :parameter_details, :subclasses
+end
+
+def parameter_details
+  return if object.parameters.empty?
+  erb(:parameter_details)
 end
 
 def subclasses