[css3-layout] Added a slightly nicer alternative syntax without double

parentheses for ::region() in the section about alternative ways to do
region-based styling.

Author: bert-github

css-template/Overview.src.html

@@ -4097,8 +4097,19 @@ <h4 id=select-after-pseudo>Style the contents of slots (region-based
 
 <p>Yet another possibility is a generic 'region()' pseudo-element:
 
-<pre>P::region(BODY::slot(c)) { color: yellow }
-EM::region(P::first-line) { font-weight: normal }</pre>
+<pre>P::region(slot(c)) { color: yellow }
+EM::region(first-line) { font-weight: normal }</pre>
+
+<p>Or without the nested parentheses:
+
+<pre>P::region(slot c) { color: yellow }
+EM::region(first-line) { font-weight: normal }</pre>
+
+<p>The name “region” may not be the best. Some alternatives are:
+
+<pre>EM::part(first-line) { font-weight: normal }
+EM::inside(first-line) { font-weight: normal }
+EM::overlap(first-line) { font-weight: normal }</pre>
 
 <p>And [[CSS3-REGIONS]] proposes an at-rule, '@region':