[css-syntax] Add change about 4/**/% to changes list.

Author: tabatkins

css-syntax-3/Overview.bs

@@ -3477,6 +3477,8 @@ Changes from the 20 February 2014 Candidate Recommendation</h3>
 
 	* Clarified on every range that they are inclusive.
 
+	* Added a column to the comment-insertion table to handle a number token appearing next to a "%" delim token.
+
 	<a href="https://github.com/w3c/csswg-drafts/milestone/5?closed=1">A Disposition of Comments is available.</a>