#17351: merge with 3.3.

diff --cc Doc/howto/logging-cookbook.rst
Simple merge

diff --cc Doc/library/contextlib.rst
Simple merge

diff --cc Doc/library/functions.rst
Simple merge

diff --cc Doc/library/unittest.mock-examples.rst
Simple merge

diff --cc Doc/library/unittest.mock.rst
Simple merge

diff --cc Misc/ACKS
Simple merge