Forgot default white point in alpha type aliases

[piegamesde]

Lch is a valid type, but Lcha is not. I have to specify the white point with Lcha<white_point::D65>. In the type alias definition, type Lcha<Wp, T = f32> = Alpha<Lch<Wp, T>, T>; should be changed to type Lcha<Wp = D65, T = f32> = Alpha<Lch<Wp, T>, T>; to remove that inconsistency.

I haven't checked all color types, but at least the Laba type suffers from this as well.

[Ogeon]

Thanks for pointing this out!

I don't remember if there was a reason for doing it that way or if it was an just oversight. Most likely a mistake or some reasoning that it would be inherited from whatever other color space is used. That last part is probably more inconvenient than helpful.