Fix type problem with URL and URLSearchParams globals

[pmmmwh]

This fixes #960 , basically duplicating the URL global shim to the types file which is exported to user-land.

[szmarczak]

Shouldn't be https://github.com/sindresorhus/got/blob/master/source/types/url/index.d.ts removed then?

Should https://github.com/sindresorhus/got/blob/master/source/types/reflect/index.d.ts be moved too? And https://github.com/sindresorhus/got/blob/master/source/types/mimic-response/index.d.ts ?

[pmmmwh]

Shouldn't be https://github.com/sindresorhus/got/blob/master/source/types/url/index.d.ts removed then?

Also should https://github.com/sindresorhus/got/blob/master/source/types/reflect/index.d.ts be moved also? And https://github.com/sindresorhus/got/blob/master/source/types/mimic-response/index.d.ts ?

1. I kept it because I think the two files signals two different problems, one about URL missing in the global types, and the other about TSC not able to output non module files. If TSC got updated, we could safely remove the change done in this PR, and if URLs got added, we can remove both. If you think this is unnecessary, I can PR to remove the duplication.
2. They don't have to be added because they are only used internally by the source. Won't bleed type errors into user land.

[szmarczak]

Honestly I don't know what's the correct solution. Just asking.

[pmmmwh]

Hi

Honestly I don't know what's the correct solution. Just asking.

Me neither, they are all workarounds for unfortunate limitations to TS, so I just wanted to make it work and move on ...