Form the docs, I know that
Much like regular pages, taxonomy list permalinks are configurable, but taxonomy term page permalinks are not.
…which is in my opinion and without the intention to offend anyone, a bit useless this way. Why would you have for example a custom taxonomy list url if the term page cannot be changed so the two cannot be the same (e.g. /autor/ for the term page and /autor/goethe as the taxonomy list).
I have also found this:
It suggests some changes to the Go code. Is it possible to include that in Hugo’s code base (I can create a PR, but is that a right solution etc?)