Update accessible name steps for optgroup

revised to incorporate latest decisions on how the naming/desc should work

html-aam/index.html

@@ -16162,11 +16162,11 @@ <h4>`optgroup` Element Accessible Name Computation</h4>
             </li>
             <li>
               If the <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a> is still empty, then: if the `optgroup` element has a
-              <a data-cite="html/form-elements.html#attr-optgroup-label">label</a> attribute use the rendered value of that attribute.
+              <a href="https://dom.spec.whatwg.org/#concept-tree-child">child</a> that is a <code>legend</code> element, then use the subtree of the first such element in the accessibility tree.
             </li>
             <li>
-              If the <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a> is still empty, then: if the `optgroup` element has a
-              <a href="https://dom.spec.whatwg.org/#concept-tree-child">child</a> that is a <code>legend</code> element, then use the subtree of the first such element in the accessibility tree.
+              If the <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a> is still empty, and there is no child `legend` element, then: 
+              if the `optgroup` element has a <a data-cite="html/form-elements.html#attr-optgroup-label">label</a> attribute use the value of that attribute, which renders as the visible label of the `optgroup`.
             </li>
             <li>
               If the <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a> is still empty, then: if the `optgroup` element has a `title` attribute, then use that attribute.
@@ -16379,11 +16379,14 @@ <h3>Accessible Description Computation</h3>
               <li>
                 an `optgroup` element which has a visible label rendered by its `label` attribute, a <a href="https://dom.spec.whatwg.org/#concept-tree-child">child</a> `legend` element, or both:
                   <ol>
-                    <li>use the value of the `label` attribute if it was not used as the <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a></li>
-                    <li>use the <a data-cite="accname-1.2/#mapping_additional_nd_te">text equivalent computation</a> of the subtree of the first `legend` element if it was not used as the
-                        <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a>.</li>
-                    <li>or if both the `label` attribute and `legend` element were used, and their concatenate the <a data-cite="accname-1.2/#mapping_additional_nd_te">text equivalent computation</a> of each by DOM order, delimited by spaces,
-                      if neither were used as the <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a>, and so long as the values of text equivalent computation of each do not match.</li>
+                    <li>
+                      use the value of the `label` attribute if it was not used as the 
+                      <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a>
+                    </li>
+                    <li>
+                      or use the <a data-cite="accname-1.2/#mapping_additional_nd_te">text equivalent computation</a> of the subtree of the 
+                      first `legend` element if it was not used as the <a data-cite="accname-1.2/#dfn-accessible-name">accessible name</a>.
+                    </li>
                   </ol>
               </li>
               <li>