[3.6]bpo-29341: Backport b942707 3.6 (GH-10299)

[3.6]bpo-29341: Backport b942707 3.6 (GH-10299)

Some methods in the os module can accept path-like objects. This is documented in the general documentation but not in the function docstrings. To keep both in sync, the docstrings need to be updated to reflect that path-like objects are also accepted..
(cherry picked from commit b942707fc23454a998323c17e30be78ff1a4f0e7)

Co-authored-by: BNMetrics <luna@bnmetrics.com>