[css-color-4][editorial] Fix Bikeshed link (w3c#13717)

Author: cdoublev

css-color-4/Overview.bs

@@ -6491,7 +6491,7 @@ Resolving values of the ''color()'' function</h3>
 	The computed value
 	is the corresponding color in its color space.
 	However, such colors must not be altered by
-	'forced colors mode'.
+	[=forced colors mode=].
 
 	<div class="example" id="ex-system-resolve">
 		For example, in this html: