[css-values-3] Update Changes list

Author: fantasai

css-values-3/Overview.bs

@@ -2040,6 +2040,15 @@ Acknowledgments</h2>
 <h2 class="no-num" id="changes">
 Changes</h2>
 
+
+	Changes since the <a href="https://www.w3.org/TR/2016/CR-css-values-3-20160929/">29 September 2016 Candidate Recommendation</a> are:
+
+	<ul>
+		<li>Inlined definition of <<position>> and removed three-value syntax
+			to allow for unambiguous combination in complex grammars.
+			(See <a href="https://lists.w3.org/Archives/Public/www-style/2017Feb/0052.html">discussion</a>.)
+	</ul>
+
 	Changes since the <a href="https://www.w3.org/TR/2015/CR-css-values-3-20150611/">11 June 2015 Candidate Recomendation</a> are:
 
 	<ul>