Release notes for 2.2.21 are incomplete, or the code is too strict

[Ned Batchelder]

It seems to me that the release note for 2.2.21 is incomplete. It says, "Specifically, empty file names and paths with dot segments will be
rejected."

But it's stricter than that: any path component causes the path to be rejected:

if name != os.path.basename(name):
    raise SuspiciousFileOperation("File name '%s' includes path elements" % name)

Is this level of strictness necessary?

[Ned Batchelder]

Looks like this is a dup of #32718.