Make sure HTML element constructors set a registry

This is covered by existing tests and helps with whatwg/dom#1379.

Author: annevk

source

@@ -12206,6 +12206,9 @@ document.createElement("bad-1");  // (2)</code></pre>
      <var>definition</var>'s <span data-x="concept-custom-element-definition-local-name">local
      name</span>.</p></li>
 
+     <li><p>Set <var>element</var>'s <span data-x="element-custom-element-registry">custom element
+     registry</span> to <var>registry</var>.</p></li>
+
      <li><p>Set <var>element</var>'s <span>custom element state</span> to "<code
      data-x="">custom</code>".</p></li>
 
@@ -12218,7 +12221,7 @@ document.createElement("bad-1");  // (2)</code></pre>
      <li><p>Return <var>element</var>.</p></li>
     </ol>
 
-    <p class="note">This occurs when author script constructs a new custom element directly, e.g.
+    <p class="note">This occurs when author script constructs a new custom element directly, e.g.,
     via <code data-x="">new MyCustomElement()</code>.</p>
    </li>
 
@@ -148434,7 +148437,7 @@ INSERT INTERFACES HERE
   Ryosuke Niwa,
   S. Mike Dierken,
   Salvatore Loreto,
-  Sam Atkins, <!-- atkinssj on GitHub -->
+  Sam Atkins, <!-- AtkinsSJ on GitHub -->
   Sam Dutton,
   Sam Kuper,
   Sam Ruby,