color-desaturate-hsl
color-desaturate-hsl is a compiled Lisp function in `color.el
'.
(color-desaturate-hsl H S L PERCENT)
Make a color less saturated by a specified amount.
Given a color defined in terms of hue, saturation, and luminance
(arguments H, S, and L), return a color that is PERCENT less
saturated. Returns a list (HUE SATURATION LUMINANCE).