fix another secure context xref

Author: Marcos Cáceres

index.html

@@ -559,9 +559,9 @@ <h2>
         </li>
         <li>Return <var>promise</var> and continue the following steps asynchronously.
         </li>
-        <li>If the <a>current settings object</a> is not a <a data-cite="secure-contexts">secure
-        context</a>, reject <var>promise</var> with a {{DOMException}} whose name is
-        "{{SecurityError}}" and terminate these steps.
+        <li>If the <a>current settings object</a> is not a <a data-cite=
+        "secure-contexts#secure-context">secure context</a>, reject <var>promise</var> with a
+        {{DOMException}} whose name is "{{SecurityError}}" and terminate these steps.
         </li>
         <li>If the <var>options</var> argument includes a non-null value for the
           `<a data-link-for="PushSubscriptionOptions">applicationServerKey</a>` attribute, run the