[css-lists-3] Add counter-set to changes list. Fixes #2640

Author: fantasai

css-lists-3/Overview.bs

@@ -1355,7 +1355,7 @@ This section documents the changes since previous publications.
 
 Use <<custom-ident>> consistently for counter names.
 
-<h3 id="changes-from-css2">Changes From CSS2.1</h3>
+<h3 id="changes-from-css2">Changes From CSS Level 2</h3>
 
 	<p>As described in the introduction section, there are significant changes in this module when
 	compared to CSS2.1.
@@ -1366,5 +1366,7 @@ Use <<custom-ident>> consistently for counter names.
 		<li>'list-style-type' now accepts a <<string>>.
 
 		<li>The ''counter-set/list-item'' predefined counter identifier has been introduced.
+
+		<li>The 'counter-set' property has been added.
 	</ol>