[css-fonts-4] Update changes

Author: svgeesus

css-fonts-4/Overview.bs

@@ -7269,6 +7269,9 @@ Changes
 <h3 id="changes-2021-07-29">Changes from the <a href="https://www.w3.org/TR/2021/WD-css-fonts-4-20210729/">29 July 2021 Working Draft</a> </h3>
 
 <ul>
+	<!-- to 16 Aug 2021 -->
+	<li>Clarified incremental requirement</li>
+	<li>A few more examples</li>
 	<li>Added incremental font technology to supports</li>
 	<li>Reduced the critical angle for oblique font matching from 20deg to 11deg, per WG resolution</li>
 	<li>Allowed font-display in @font-feature-values (the prose allowed it but the grammar did not)</li>