chore(doc-gen): HTML escape method signatures

Closes angular#1249
Closes angular#1257

Author: petebacondarwin

docs/dgeni-package/templates/lib/paramList.html

@@ -1,7 +1,7 @@
 {% macro paramList(params) -%}
   {%- if params -%}<span class="params">(
     {%- for param in params -%}
-      <span class="param">{$ param $}{% if not loop.last %}, {% endif %}</span>
+      <span class="param">{$ param | escape $}{% if not loop.last %}, {% endif %}</span>
     {%- endfor %})</span>
   {%- endif %}
 {%- endmacro -%}