Explicit types are too verbose

[Siegrift]

Currently, if someone wants to type a custom error, they need to do:

    const goRes = await go<Promise<AxiosResponse>, AxiosError>(async () => post(req), {
      delay: { type: 'static', delayMs: 500 },
    });

notice the Promise<...> which seems unnecessary, because go will always return a Promise. The user should only provide the content of the promise.