Make example token easier to understand

packages/mcp/www/index.html

@@ -27,10 +27,11 @@
     </ul>
 
     <h2>Claim Token</h2>
+    <p>Tokens look like <samp>foo:xabab-babab-babax</samp>.</p>
     <form action="claim.cgi" method="post">
       <fieldset>
         team hash:<input name="t" size="8">
-        token:<input name="k" size="30" value="example:xabab-babab-babax">
+        token:<input name="k" size="30">
         <input type="submit" value="claim">
       </fieldset>
     </form>