[X] Adds support for loading TypeScript config files (.size-limit.ts, .size-limit.mts, .size-limit.cts).
[X] Adds fixtures to test every single file extension/module type combo to make sure the library is fully capable of handling different configuration flles.
[X] Test performance to make sure extra overhead was not accumulated.
This PR:
jiti
as a dependency..size-limit.ts
,.size-limit.mts
,.size-limit.cts
).