Make option disabledness look for ancestor optgroups

Now that option elements can be descendants of optgroup elements instead of just children, the disabledness algorithm should look for ancestors intead of just a parent optgroup element.

Fixes #11707.

Author: josepharhar

source

@@ -56987,11 +56987,29 @@ interface <dfn interface>HTMLOptionElement</dfn> : <span>HTMLElement</span> {
 
   <div algorithm>
   <p>The <dfn element-attr for="option"><code data-x="attr-option-disabled">disabled</code></dfn>
-  attribute is a <span>boolean attribute</span>. An <code>option</code> element is <dfn
-  data-x="concept-option-disabled">disabled</dfn> if its <code
-  data-x="attr-option-disabled">disabled</code> attribute is present or if it is a child of an
-  <code>optgroup</code> element whose <code data-x="attr-optgroup-disabled">disabled</code>
-  attribute is present.</p>
+  attribute is a <span>boolean attribute</span>. An <code>option</code> element <var>option</var> is
+  <dfn data-x="concept-option-disabled">disabled</dfn> if the following steps return true:</p>
+
+  <ol>
+   <li><p>If <var>option</var>'s <code data-x="attr-option-disabled">disabled</code> attribute is
+   present, then return true.</p></li>
+
+   <li>
+    <p>For each <var>ancestor</var> of <var>insertedOption</var>'s <span
+    data-x="ancestor">ancestors</span> in reverse <span>tree order</span>:</p>
+
+    <ol>
+     <li><p>If <var>ancestor</var> is a <code>select</code>, <code>hr</code>, or <code>option</code>
+     element, then return false.</p></li>
+
+     <li><p>If <var>ancestor</var> is an <code>optgroup</code> element, then return true if
+     <var>ancestor</var>'s <code data-x="attr-optgroup-disabled">disabled</code> attribute is
+     present; otherwise false.</p></li>
+    </ol>
+   </li>
+
+   <li><p>Return false.</p></li>
+  </ol>
   </div>
 
   <div w-nodev>