[css-2022] Add CSS Color 4 to "Official definition"

[svgeesus]

For Snapshot 2021, I had proposed moving Color 4 to the "Official definition" list, on the grounds that it has been fully implemented twice (Safari, BFO) and is generally the current implementation target. We had also moved some things to CSS Color 5, to aid the stability and near-term implementation status for CSS Color 4. However, the counter-argument was that it was not in CR yet, which was fair enough.

Given that it is now in CR:

• CSS Color 4 to Candidate Recommendation #7393

and also given that we added an early release approval for CSS Images 4 non-sRGB gradients (which depends on the Color Interpolation section of CSS Color 4), I believe that Snapshot 2022 should move CSS Color 4 up from "Fairly Stable" to "Official Definition", replacing the increasingly dated and restrictive CSS Color 3 in that section.

[css-meeting-bot]

The CSS Working Group just discussed [css-2022] Add CSS Color 4 to "Official definition", and agreed to the following:

• RESOLVED: Add Color 4 to snapshot

The full IRC log of that discussion

<emilio> topic: [css-2022] Add CSS Color 4 to "Official definition"
<fantasai> +1 to adding to snapshot
<emilio> github: https://github.com//issues/7455
<TabAtkins> +1
<emilio> RESOLVED: Add Color 4 to snapshot
<chris> great!