Expose more internal types

[bombillazo]

Hello,

For use, the ArrayElement type is super convenient, yet we can only import it from the type-fest/source/internal path. In Deno this causes some import issues so I was wondering if the library could export ArrayElement directly from the main project?

[sindresorhus]

We are happy to expose more of the internal types. Someone needs to do the work write better docs, tests, etc for that type.

https://github.com/sindresorhus/type-fest/blob/main/.github/contributing.md#submitting-a-new-type