Added a note about coarse language to the rules.

Rules loosely enforced at the whim of room owners are confusing/unhelpful for new users.

Author: wimglenn

sopy/templates/pages/chatroom.html

@@ -29,6 +29,7 @@ <h2>Rules</h2>
 
     <ol>
         <li><a href="http://chat.stackoverflow.com/faq#nice">Be nice.</a></li>
+        <li>No swearing.  Expletives are <a href="https://meta.stackexchange.com/a/22233/162650">not acceptable behavior</a> on any Stack Exchange site.</li>
         <li>If nobody responds to your question, that means no-one in the room is able to help (either because they don't know,
             or are too busy to answer right now). Please don't spam the room with further requests for help on the same question.
             It will only annoy people and make them less likely to want to help you in future.</li>