Support HSL with hue units in arbitrary values

[adamwathan]

Fixes #6709.

This PR updates our color parser to support hsl colors in these formats:

hsl(0deg, 30%, 60%)
hsl(0rad, 30%, 60%)
hsl(0grad, 30%, 60%)
hsl(0turn, 30%, 60%)
hsla(0deg, 30%, 60%, 0.5)
hsla(0rad, 30%, 60%, 0.5)
hsla(0grad, 30%, 60%, 0.5)
hsla(0turn, 30%, 60%, 0.5)
hsl(0deg 30% 60%)
hsl(0rad 30% 60%)
hsl(0grad 30% 60%)
hsl(0turn 30% 60%)
hsl(0deg 30% 60% / 0.5)
hsl(0rad 30% 60% / 0.5)
hsl(0grad 30% 60% / 0.5)
hsl(0turn 30% 60% / 0.5)

Previously, using any unit after the hue value would fail our color detection and therefore not work properly with arbitrary value utilities like bg-hsl(0rad,10%,60%).