Truly algebraic Variant and Nullable

[jmh530]

On Wednesday, 16 December 2020 at 15:58:21 UTC, 9il wrote:
> [snip]
>
> Thanks! Maybe, but mir-core is quite small itself and 
> mir.algebraic is the only part that would be extended or 
> updated in the near future. Other parts are quite stable. If 
> there would be a strong reason to split it, we can do it.

What about making it into a sub-package, as in here [1]?

[1] 
https://github.com/atilaneves/unit-threaded/tree/master/subpackages