[css-color-5] fix mention of powerless components

[romainmenke]

see : #8609

https://drafts.csswg.org/css-color-4/#specifying-lab-lch

If the chroma of an LCH color is 0%, the hue component is powerless. If the lightness of an LCH color (after clamping) is 0%, or 100%, both the hue and chroma components are powerless.

https://drafts.csswg.org/css-color-4/#specifying-oklab-oklch

If the chroma of an Oklch color is 0% or 0, the hue component is powerless. If the lightness of an Oklch color is 0% or 0, or 100% or 1.0, both the hue and chroma components are powerless.

[romainmenke]

@svgeesus Could you take a look at this when you have time? 🙇

[w3cbot]

svgeesus marked as non substantive for IPR from ash-nazg.