[css-color-5] The relative form of of the rgb() function should allow none as the alpha component

[weinig]

All other the relative color functions allow the alpha component to be specified / [<alpha-value> | none] ]? except the relative rgb() function which is currently specified as [ / <alpha-value> ]?.

I am guessing this is just a mistake, but if it is intentional, it would be good to call it out in prose as well.

[svgeesus]

Thanks! Yes, a mistake.