[`pylint`] Stabilize `shallow-copy-environ` (`PLW1507`) (#16627)
Summary
--
Stabilizes PLW1507. The tests were already in the right place, and I
just tidied the docs a little bit.
Test Plan
--
1 issue from 2 weeks ago but just suggesting to mark the fix unsafe. The
shallow vs deep copy *does* change the program behavior, just usually in
a preferable way.
