[css-values-5] Fix and rename random grammar

[cdoublev]

The random-*() grammar is slightly broken since 33682af.

They now take a <random-key> argument renamed from <random-cache-key>. It still produces auto | <random-name> | fixed <number [0,1)> but <random-name> is left undefined, because its definition and production rule now use <random-cache-key>, which was probably not intentional.

This PR tries to fix this but since fixed <number [0,1)> is not a random (cache) key but a random base value, and since auto produces but is not a random name, and resolves to a random base value, I suggest to introduce <random-base-value> to replace <random-key>.

[fantasai]

I think this problem is fixed in https://github.com/w3c/csswg-drafts/pull/13845/changes ?

Or is something still broken?

[cdoublev]

Yes, it is fixed by #13845.

Not exactly something broken, but some things that generally seem to lack precision:

• <random-key> produces fixed <number>, which is a random base value, not a random cache name/key
• the random cache name is built from the <random-cache-key> but is not entirely specified with it

The <random-cache-key> specifies the random cache name

https://drafts.csswg.org/css-values-5/#typedef-random-cache-key

But I assume these will be fixed as you refine these terms and definitions.