Editorial: group area's shape with other IDL attributes

As of d56b5d6 it's no longer limited to known values and as such does not warrant its own line.

Fixes #10303.

source

@@ -41912,16 +41912,13 @@ interface <dfn interface>HTMLAreaElement</dfn> : <span>HTMLElement</span> {
   <p>The IDL attributes <dfn attribute for="HTMLAreaElement"><code
   data-x="dom-area-alt">alt</code></dfn>, <dfn attribute for="HTMLAreaElement"><code
   data-x="dom-area-coords">coords</code></dfn>, <dfn attribute for="HTMLAreaElement"><code
+  data-x="dom-area-shape">shape</code></dfn>, <dfn attribute for="HTMLAreaElement"><code
   data-x="dom-area-target">target</code></dfn>, <dfn attribute for="HTMLAreaElement"><code
   data-x="dom-area-download">download</code></dfn>, <dfn attribute for="HTMLAreaElement"><code
   data-x="dom-area-ping">ping</code></dfn>, and <dfn attribute for="HTMLAreaElement"><code
   data-x="dom-area-rel">rel</code></dfn>, each must <span>reflect</span> the respective content
   attributes of the same name.</p>
 
-  <p>The IDL attribute <dfn attribute for="HTMLAreaElement"><code
-  data-x="dom-area-shape">shape</code></dfn> must <span>reflect</span> the <code
-  data-x="attr-area-shape">shape</code> content attribute.</p>
-
   <p>The IDL attribute <dfn attribute for="HTMLAreaElement"><code
   data-x="dom-area-rellist">relList</code></dfn> must <span>reflect</span> the <code
   data-x="attr-hyperlink-rel">rel</code> content attribute.</p>