Add code of conduct callout

Author: Jon Wayne Parrott

warehouse/templates/pages/help.html

@@ -252,6 +252,7 @@ <h3 id="new-classifier">{{ new_classifier() }}</h3>
         <p>
           If you would like to request a new Trove classifer please file a bug on our <a href="https://github.com/pypa/warehouse/issues" target="_blank" rel="noopener">issue tracker</a>. Please include the name of the requested classifier and a brief justification of why it is important.
         </p>
+        {{ code_of_conduct() }}
 
         <h3 id="feedback">{{ feedback() }}</h3>
         <p>