[css-values] Resolution of math functions

[Loirooriol]

From https://drafts.csswg.org/css-values-4/#calc-notation,

A math function can be used wherever <length>, <frequency>, <angle>, <time>, <percentage>, <number>, or <integer> values are allowed.

From https://drafts.csswg.org/css-values-4/#calc-type-checking,

A math function has a resolved type, which is one of <length>, <frequency>, <angle>, <time>, <percentage>, <number>, or <integer>.

From https://drafts.csswg.org/css-values-4/#type-checking-exprs,

A math function resolves to <length>, <angle>, <time>, <frequency>, <resolution>, <flex>, or <percentage> according to which of those productions its type matches.

Why are <number> and <integer> in #1 and #2 but not in #3?

Why are <resolution> and <flex> in #3 but not in #1 nor #2?

Is it necessary to repeat this list three times?

[tabatkins]

Why are <number> and <integer> in #1 and #2 but not in #3?

Accident.

Why are <resolution> and <flex> in #3 but not in #1 nor #2?

For flex, we have w3c/css-houdini-drafts#734 still open.

I... actually didn't realize calc() wasn't defined over <resolution>. I'll add it to that issue.

Is it necessary to repeat this list three times?

No, I need to do some more cleanup.

[tabatkins]

Fixed the first.

Went ahead and edited the spec to fix the second, tho technically we do need the resolution to make it valid. But I think it's a foregone conclusion.

Fixed the third by removing one of the lists, along with a lot of now-redundant instructions for how to determine the type of a math function. Still need the other two, as far as I can tell.