[css-values] Move parentheses and forward-port fix for w3c#708.

Author: fantasai

css-values-3/Overview.bs

@@ -1110,9 +1110,10 @@ Absolute lengths: the ''cm'', ''mm'', ''q'', ''in'', ''pt'', ''pc'', ''px'' unit
 		<li>by relating the <a value>pixel unit</a> to the <a>reference pixel</a>.
 	</ol>
 
-	For print media and similar high-resolution devices,
+	For print media,
 	the anchor unit should be one of the standard physical units (inches, centimeters, etc).
-	For lower-resolution devices,
+	For screen media (including high-resolution devices),
+	lower-resolution devices,
 	and devices with unusual viewing distances,
 	it is recommended instead that the anchor unit be the pixel unit.
 	For such devices it is recommended that the pixel unit

css-values/Overview.bs

@@ -1198,7 +1198,8 @@ Absolute lengths: the ''cm'', ''mm'', ''q'', ''in'', ''pt'', ''pc'', ''px'' unit
 
 	For print media,
 	the anchor unit should be one of the standard physical units (inches, centimeters, etc).
-	For screen media (including high-resolution devices, lower-resolution devices,
+	For screen media (including high-resolution devices),
+	lower-resolution devices,
 	and devices with unusual viewing distances),
 	it is recommended instead that the anchor unit be the pixel unit.
 	For such devices it is recommended that the pixel unit