[css-color-5] serializing all RCS not just color()

Author: svgeesus

css-color-5/Overview.bs

@@ -1151,7 +1151,7 @@ the winning color.
 	"color(display-p3 0.45 0.08 0.05)".
 </div>
 
-Serializing relative color() {#serial-relative-color}
+Serializing relative color functions {#serial-relative-color}
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 The serialization of the result of a relative color function