Remove ISSUE label for "Simplify embellished operator?"

closes w3c/mathml#115

Author: fred-wang

index.html

@@ -1429,7 +1429,6 @@ <h4>Operator, Fence, Separator or Accent <code>&lt;mo&gt;</code></h4>
           </ul>
           <section id="embellished-operators">
             <h5>Embellished operators</h5>
-            <div class="issue" data-number="115">Simplify embellished operator?</div>
             <p>
               A <a>MathML Core element</a> is an
               <dfn>embellished operator</dfn>