Define :enabled by reference to "actually disabled"

This makes it obvious that the list of conditions for :enabled and
:disabled are inverses of each other.

Removes a no-longer-accurate comment about disabling a/area/link
elements.

source

@@ -67368,7 +67368,7 @@ contradict people?
   <h3>Disabled elements</h3>
 
   <p>An element is said to be <dfn data-x="concept-element-disabled">actually disabled</dfn> if it
-  one of the following:</p>
+  is one of the following:</p>
 
   <ul>
 
@@ -67736,34 +67736,9 @@ Demos:
    <dd>
 
     <p>The <code data-x="selector-enabled">:enabled</code> <span>pseudo-class</span> must match any
-    element that is one of the following:</p>
-
-    <ul>
-
-<!-- These are commented out because they currently can't be disabled and for some reason the
-     CSS specs say that :enabled should only match elements that can be disabled.
-     <li>an <code>a</code> element that has an <code data-x="attr-hyperlink-href">href</code> attribute</li>
-     <li>an <code>area</code> element that has an <code data-x="attr-hyperlink-href">href</code> attribute</li>
-     <li>a <code>link</code> element that has an <code data-x="attr-link-href">href</code> attribute</li>
--->
-
-     <li>a <code>button</code> element that is not <span data-x="concept-fe-disabled">disabled</span></li>
-
-     <li>an <code>input</code> element that is not <span data-x="concept-fe-disabled">disabled</span></li>
-
-     <li>a <code>select</code> element that is not <span data-x="concept-fe-disabled">disabled</span></li>
-
-     <li>a <code>textarea</code> element that is not <span data-x="concept-fe-disabled">disabled</span></li>
-
-     <li>an <code>optgroup</code> element that does not have a <code data-x="attr-optgroup-disabled">disabled</code> attribute</li>
-
-     <li>an <code>option</code> element that is not <span data-x="concept-option-disabled">disabled</span></li>
-
-     <li>a <code>menuitem</code> element that does not have a <code data-x="attr-menuitem-disabled">disabled</code> attribute</li>
-
-     <li>a <code>fieldset</code> element that is not a <span data-x="concept-fieldset-disabled">disabled fieldset</span></li>
-
-    </ul>
+    <code>button</code>, <code>input</code>, <code>select</code>, <code>textarea</code>,
+    <code>optgroup</code>, <code>option</code>, <code>menuitem</code>, or <code>fieldset</code>
+    element that is not <span data-x="concept-element-disabled">actually disabled</span>.</p>
 
    </dd>
 
@@ -119757,6 +119732,7 @@ INSERT INTERFACES HERE
   Rich Clark,
   Rich Doughty,
   Richa Rupela,
+  Richard Gibson,
   Richard Ishida,
   Rigo Wenning,
   Rikkert Koppes,