[css-color-5] Linking fix

Author: tabatkins

css-color-5/Overview.bs

@@ -65,8 +65,8 @@ Introduction {#intro}
 	like yellow and blue, can have the same HSL lightness).
 
 	This module adds three functions:
-	''color-mix'',
-	''color-contrast'',
+	''color-mix()'',
+	''color-contrast()'',
 	and [[#colormodify|a way to modify colors]].
 
 	The perceptually uniform ``lch()`` colorspace