[css-color-4] more than 2 predefined now

Author: svgeesus

css-color-4/Overview.bs

@@ -2355,7 +2355,7 @@ Predefined colorspaces: ''srgb'', ''display-p3'', ''a98-rgb'', ''prophoto-rgb''
 <h4 id="predefined-to-lab">
 Converting predefined colorspaces to Lab</h4>
 
-	For both predefined color spaces,
+	For all predefined color spaces,
 	conversion to Lab requires several steps,
 	although in practice all but the first step are linear calculations and can be combined.