Editorial: refactor the list of the descendant browsing contexts

A browsing context isn't "nested through" an element.

source

@@ -78642,29 +78642,23 @@ dictionary <dfn>DragEventInit</dfn> : <span>MouseEventInit</span> {
   is the (ordered) list returned by the following algorithm:</p>
 
   <ol>
-
    <li><p>Let <var>list</var> be an empty list.</p></li>
 
    <li>
-
-    <p>For each <span>child browsing context</span> of <var>d</var> that is <span data-x="browsing
-    context nested through">nested through</span> an element that is <span data-x="in a document">in
-    the <code>Document</code></span> <var>d</var>, in the <span>tree order</span> of the elements
-    nesting those <span data-x="browsing context">browsing contexts</span>, run these substeps:</p>
+    <p>For each <span>nested browsing context</span> <var>nestedBC</var> of a <span>browsing context
+    container</span> that is <span data-x="in a document">in the <code>Document</code></span>
+    <var>d</var>, in the <span>tree order</span> of the <span data-x="browsing context
+    container">browsing context containers</span>:</p>
 
     <ol>
+     <li><p>Append <var>nestedBC</var> to <var>list</var>.</p>
 
-     <li><p>Append that <span>child browsing context</span> to the list <var>list</var>.</p>
-
-     <li><p>Append the <span>list of the descendant browsing contexts</span> of the <span>active
-     document</span> of that <span>child browsing context</span> to the list <var>list</var>.</p></li>
-
+     <li><p>Append the <span>list of the descendant browsing contexts</span> of
+     <var>nestedBC</var>'s <span>active document</span> to <var>list</var>.</p></li>
     </ol>
-
    </li>
 
-   <li><p>Return the constructed <var>list</var>.</p></li>
-
+   <li><p>Return <var>list</var>.</p></li>
   </ol>
 
   <p>A <code>Document</code> is said to be <dfn data-export="" data-dfn-for="Document">fully