Add CSS Environment Variables env()

[ausi]

See #3787.

env() is supported since Safari 11, Chrome 69, Opera 56.

[Malvoz]

Want to add MS Edge feature suggestion to that?
https://wpdev.uservoice.com/forums/257854-microsoft-edge-developer/suggestions/34589707-css-environment-variables

Should probably extend keywords to "CSS variables" here aswell.

[ausi]

@Malvoz done.

[Malvoz]

Thanks, I have further requests on that though - if a user searches explicitly for e.g. "css env()" or "css variables" this would not show with the current keywords:

env,safe-area-inset,constant,variables.

Can I bother you with an updated list on that?

css env(),constant(),css variables,safe-area-inset-top,safe-area-inset-right,safe-area-inset-bottom,safe-area-left.

I think it is a tad bit overkill with the safe-area-*, but users will find what they're looking for.

[ausi]

@Malvoz done.

[Fyrd]

Thanks!

[kiding]

caniuse/features-json/css-env-function.json

Line 348 in 12e8ced

"shown":false

Since there is no pending review, I believe shown should be true unless there is any particular reason.

EDIT: Now fixed! #3787 (comment)