Issue #18594:  Fix the fallback path in collections.Counter().
Issue #19137: The pprint module now correctly formats instances of set and
frozenset subclasses.
Drop buildbottouch again; the master is using "make touch" now.
Issue #19147: Fix docstring for fcntl.flock to refer to correct man section.
Issue #18037: 2to3 now escapes '\u' and '\U' in native strings.
Issue #19014: memoryview.cast() is now allowed on zero-length views.
[issue19151] Fix docstring and use of _get_suppported_file_loaders() to reflect 2-tuples.
[issue19152] Add ExtensionFileLoader.get_filename().
Fix typo.
[issue19152] Revert 832579dbafd6.
Close #19160: Inconsistent size for GIL release in hashlib
Close #19160: Inconsistent size for GIL release in hashlib
Issue #18594:  Make the C code more closely match the pure python code.
#19166: use an unused var in a test.  Patch by Vajrasky Kok.
#19067: use imperative mood in range object docstrings.  Patch by Marco Buttu.
#19068: use imperative mood in complex object docstrings.  Patch by Marco Buttu.
#19069: use imperative mood in float object docstrings.  Patch by Marco Buttu.
Issue #19171:  speed some cases of 3-argument long pow().

Reduce the base by the modulus when the base is larger than
the modulus.  This can unboundedly speed the "startup costs"
of doing modular exponentiation, particularly in cases where
the base is much larger than the modulus.  Original patch
by Armin Rigo, inspired by https://github.com/pyca/ed25519.
Minor clean-up of function parameters in random().
Issue 14927: Remove a docstring line that is no longer applicable.