Document usage of the existing `--prompt` option in the command line help.

* Add tests for Counter order.  No behavior change.

* Update docs and tests

* Fix doctest output and capitalization

Trying to assign a value to __debug__ using the assignment operator is supposed to fail, but
a missing check for forbidden names when setting the context in the ast was preventing this behaviour. 

read() returns bytes for a file opened in binary mode,
so b'' should be used as a sentinel instead of ''.
Otherwise the loop will be infinite.

Explicitly reinitialize this every eval *just in case* someone is
calling into an embedded Python where they don't care about an uncaught
KeyboardInterrupt exception (why didn't they leave
`config.install_signal_handlers` set to `0`?!?) but then later call
`Py_Main()` itself (which *checks* this flag and dies with a signal after
its interpreter exits).  We don't want a previous embedded interpreter's
uncaught exception to trigger an unexplained signal exit from a future
`Py_Main()` based one.

https://bugs.python.org/issue31982

 Fix a crash on fork when using subinterpreters.

https://bugs.python.org/issue35584

Fix test_ssl for strict OpenSSL configuration like RHEL8 strict crypto policy.
Use older TLS version for minimum TLS version of the server SSL context if
needed, to test TLS version older than default minimum TLS version.

Allow to add HTTP headers to XML-RPC requests sent to the server.

From: https://mail.python.org/pipermail/docs/2018-December/038583.html

`object.__new__` and `object.__init__` do take one argument each,
they just don't take extra user supplied arguments.

Patch by Sanyam Khurana.

It checks that a SyntaxWarning is raised when compile specified
statement, that it is raised only once, that it is converted to
a SyntaxError when raised as exception, and that both warning and
exception objects have corresponding attributes.

bpo-34572: change _pickle unpickling to use import rather than retrieving from sys.modules (GH-9047)

Fix C implementation of pickle.loads to use importlib's locking mechanisms, and thereby avoid using partially-loaded modules.

Need to reset capturing groups between two SRE(match) callings in loops, this fixes wrong capturing groups in rare cases.

Also add a missing index in re.rst.

The wrong NEWS snippet was inadvertently included in
GH-11500, this switches to the correct one.


https://bugs.python.org/issue35704

https://bugs.python.org/issue35704

bpo-35942: Improve the error message if __fspath__ returns invalid types in path_converter (GH-11831)

The error message emitted when returning invalid types from __fspath__ in interfaces that allow passing PathLike objects has been improved and now it does explain the origin of the error.

Not using `__class_getitem__()` fallback if there is a non-subcriptable metaclass was caused by a certain asymmetry between how `PySequenceMethods` and `PyMappingMethods` are used in `PyObject_GetItem`. This PR removes this asymmetry. No tests failed, so I assume it was not intentional.

Fix  Modules/_testmultiphase.c so that it exits with non-zero status on AIX just as other systems do (non zero exit status, e.g. as result of a segmentation fault) when a NULL pointer is accessed for data.


https://bugs.python.org/issue34720

It makes the existing smaller test more readable and robust at the same time.

The execution of a shell in interactive mode from CI and buildbot test automation wasn't working out.  What would work locally in our terminals would only work within a fraction of automation systems.  The integration test was a nice to have.  painful.  deleting. :)