Markup: remove stray </ins> tag (#1791)

This correction was noted here: #1791 (comment)
but omitted in the PR merge.

spec.html

@@ -18010,7 +18010,7 @@ <h1>EnumerateObjectProperties ( _O_ )</h1>
 
         <emu-note>
           <p>Hosts are not required to implement the algorithm in <emu-xref href="#sec-%foriniteratorprototype%.next"></emu-xref> directly. They may choose any implementation whose behavior will not deviate from that algorithm unless one of the constraints in the previous paragraph is violated.</p>
-          <p>The following is an informative definition of an ECMAScript generator function that conforms to these rules:</ins></p>
+          <p>The following is an informative definition of an ECMAScript generator function that conforms to these rules:</p>
           <pre><code class="javascript">
             function* EnumerateObjectProperties(obj) {
               const visited = new Set();