[css-color-5] Fix token linking

Author: LeaVerou

css-color-5/Overview.bs

@@ -101,7 +101,7 @@ Mixing colors: the ''color-mix()'' function {#color-mix}
 
 <pre class='prod'>
 	<dfn>&lt;color-adjuster></dfn> = [
-			  <<rgb-adjuster>> | <<hsl-adjuster>> | <<hwb-adjuster>>
+			  <<srgb-adjuster>> | <<hsl-adjuster>> | <<hwb-adjuster>>
 			| <<xyz-adjuster>> | <<lab-adjuster>> | <<lch-adjuster>>
 		] || alpha
 	<dfn>&lt;srgb-adjuster></dfn> = red || green || blue