Add appendFileExtension option for referencing back to origional types

[hongkongkiwi]

I'm using deno and it requires explicit .ts extensions when importing files locally.

So for example this will not work:
import { type PortKeyConfig } from "./../types/schemas";

Instead it must be:
import { type PortKeyConfig } from "./../types/schemas.ts";

Using node with ECMAScript also requires .js to be added, so I think it's a valuable option either way.

Could you help to add a config value where I can force the file extension to be added? e.g. appendFileExtension: '.ts' or something like that?

[tvillaren]

Hello,
Thanks for reporting, I believe this is a duplicate of #259, right?

Feel free to open a PR if you have some time to help the library strive! 🙏

[hongkongkiwi]

Oh yes it is a duplicate and funnily enough we have the same workaround ;)