Feature request: Retrieve user from token

[ikasoba]

Is your feature request related to a problem? Please describe.
I am trying to build a client for misskey in golang.
I was looking for a library for misskey and found this great library and decided to use it. However, it seems that there is no function (like /api/i) to get a user from a token.
Sorry if I just don't know it.

Describe the solution you'd like
I would like to add the ability to retrieve the user assigned to a token.

I've written a Pull Request to resolve this issue, and I'd like you to Merge it if this is not a problem.

Describe alternatives you've considered

Additional context

[yitsushi]

Resolved by #100