[3.9] bpo-40486: Specify what happens if directory content change diring iteration (GH-22025) (GH-22093)



(cherry picked from commit 306cfb3a37e1438f6ba9f0a9f3af3c00aae4ec64)


Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
3 files changed