[css-values-4] Fix heading.

Author: fantasai

css-values-4/Overview.bs

@@ -4915,13 +4915,13 @@ Acknowledgments</h2>
 Changes</h2>
 
 <h3 class=no-num id="changes-recent">
-Changes Since the Jan 13 2019 Working Draft</h3>
+Recent Changes</h3>
 
 	Changes since <a href="https://www.w3.org/TR/2020/WD-css-values-4-20201111/">11 November 2020 WD</a>
 	(this is a subset of [[#additions-L3]]):
 
 	<ul>
-		<li>Updated interpolation of colors to reference [[CSS-COLOR-4]].
+		<li>Updated interpolation of colors to reference [[CSS-COLOR-4]] instead of [[CSS-COLOR-3]].
 		<li>Added the ''svh'', ''svw'', ''svi'', ''svb'', ''svmin'', and ''svmax'' [=small viewport-percentage units=]
 			and ''dvh'', ''dvw'', ''dvi'', ''dvb'', ''dvmin'', and ''dvmax'' [=dynamic viewport-percentage units=].
 			(<a href="https://github.com/w3c/csswg-drafts/issues/4329">Issue 4329</a> and