[PATCH 0/2] A couple minor _versioned_namespace patches

[Tom Tromey]

While I was working on the flake8/black patches, flake8 pointed out a
bug in xmethods.py.  This is fixed in patch 1.  Then I found the
checks of _versioned_namespace to be a bit odd, so I wrote patch 2.

Tested on x86-64 Fedora 36.

Tom