[css-color-4][editorial] add wpt

Author: svgeesus

css-color-4/Overview.bs

@@ -6692,6 +6692,8 @@ animation/color-composition.html
 animation/color-interpolation.html
 animation/opacity-interpolation.html
 color-mix-basic-001.html
+color-mix-currentcolor-visited.html
+color-mix-currentcolor-visited-getcomputedstyle.html
 nested-color-mix-with-currentcolor.html
 
 parsing/color-mix-out-of-gamut.html