[css-color-4][editorial] Add WPT for PNG cICP in apng

Author: svgeesus

css-color-4/Overview.bs

@@ -764,6 +764,7 @@ Transparency: the 'opacity' property</h3>
 
 	<wpt pathprefix="/png">
 		cicp-chunk.html
+		apng/fDAT-inherits-cICP.html
 	</wpt>
 
 	If the color profile or other identifying information is invalid, the image is treated as [=untagged images=]