fix: update get element tag name to use dom element qualified name (#1968)

Author: juliandescottes

index.html

@@ -5821,8 +5821,8 @@ <h4><dfn>Get Element Tag Name</dfn></h4>
   of <a>trying</a> to <a>get a known element</a>
   with <var>URL variables</var>["<code>element id</code>"].
 
- <li><p>Let <var>qualified name</var> be the result of getting
-  <var>element</var>&apos;s {{Element/tagName}} IDL attribute.
+ <li><p>Let <var>qualified name</var> be <var>element</var>&apos;s
+  <a data-cite=dom data-xref-for=Element>qualified name</a>.
 
  <li><p>Return <a>success</a> with data <var>qualified name</var>.
 </ol>