Name based color detection

[Lukas Malkmus]

I would love to see named based color detection as a feature, so termenv can be an even better drop in replacement for libraries like ansicolor:

// c := ansicolor.ColorCode("white")

// Becomes ...

c := termenv.ColorProfile().Color("white").Sequence(false)

[Christian Muehlhaeuser]

You can kind of do that (even though not quite as straight-forward, admittedly) with the help of gamut: https://github.com/muesli/gamut