Fix "inclusive descendant navigables" usage in page visibility

Closes #9758.

Author: domenic

source

@@ -77229,7 +77229,7 @@ END:VCARD</pre>
 
   <ol>
    <li><p>Let <var>navigables</var> be the <span>inclusive descendant navigables</span> of
-   <var>traversable</var>.</p></li>
+   <var>traversable</var>'s <span data-x="nav-document">active document</span>.</p></li>
 
    <li>
     <p><span data-x="list iterate">For each</span> <var>navigable</var> of <var>navigables</var>