[color-scale] Highlight min/max of certain coordinate

[LeaVerou]

It would be really useful with both charts and scales is a way to style the accent color differently, i.e. the one with peak chroma. Obviously we'd want something more generic than that, e.g. a way to highlight the min and max for any coord or even for deltas/contrasts.

So it would have the same syntax as the value part of the info attribute. Maybe it could even piggyback on it, e.g. info="L: oklch.l, C: oklch.c (max: accent), H: oklch,h" which would add accent to that swatch's part so it can be styled via ::part(accent). Both min and max would be able to be specified, in any order (e.g. info="L: oklch.l (min: darkest, max: lightest), C: oklch.c (max: accent), H: oklch,h")

I really like this, actually. it's nice, short, and readable for the common case, but allows pretty complex things to be specified as well.