AccessTokenError is never used as a Go error. In fact, it is returned as a *AccessTokenError (which would result in a `nil` error when cast). Rename the struct to a more accurate name and remove the unused `Error() string` method to prevent future confusion. Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/11595 Reviewed-by: Gusted <gusted@noreply.codeberg.org> Co-authored-by: Oliver Eikemeier <eikemeier@fillmore-labs.com> Co-committed-by: Oliver Eikemeier <eikemeier@fillmore-labs.com>