Allow typescript configuration files

[ecstrema]

Describe the problem

I'd like to use typescript configuration files.

I've needed it twice in the past week, first to use a custom preprocessor located in the src directory, and second time to use another package in the same monorepo.

It would also enable intellisense and general better dx.

Describe the proposed solution

This should be fairly easy to implement with unconfig. I've myself used it a few times. The package is reliable, small and efficient, although the documentation can also use these adjectives.

Importance

nice to have

[bluwy]

Duplicate of #2576

[ecstrema]

see #4105