scale-color() produces incorrect colors

[nex3]

LibSass's scale-color() function output doesn't match that of Dart Sass or Ruby Sass in a number of cases:

scale-color(turquoise, $saturation: 24%, $lightness: -48%)
  should be #10867a, is actually #0d897c
scale-color(plum, $saturation: 67%)
  should be #f489f4, is actually #e895e8
scale-color(plum, $saturation: 100%)
  should be #ff7eff, is actually #ed90ed

There are likely other cases that are invalid as well.

[zwass]

This seems to be due to

libsass/src/fn_colors.cpp

Line 507 in 2c22d56

if (sscale) c->s(c->s() + sscale * (sscale > 0.0 ? 100.0 - c->l() : c->s()));

incorrectly using luminance rather than saturation in the ternary.