- at least as of TS 2.1: https://www.typescriptlang.org/docs/handbook/utility-types.html#partialtype
- we have a peerDep on TS >=2.4, so should definitely be compatible
- and TS is on ~4.6 at this point, so that's _really_ old
- remove the file and the declarations and declaration maps
- don't rebuild as that's usually done as a separate commit