These stubs are identical in Python 2 and 3, but I believe they
should not be merged, because there are numerous other modules
in the encodings package, and some only exist in some Python
versions. I don't think we can support that in the 2and3
directory.
CONTRIBUTING.md says to prefer ... Not the most impactful change but fixing
these will allow us to lint for it in the future and get a consistent style.