This change, which follows the behavior of C stdio's fdopen and Python 2's file object, allows pipes to be opened in append mode.

open(), io.open(), codecs.open() and fileinput.FileInput no longer
accept "U" ("universal newline") in the file mode. This flag was
deprecated since Python 3.3.

* Use the 'p' format unit instead of manually called PyObject_IsTrue().
* Pass boolean value instead 0/1 integers to functions that needs boolean.
* Convert some arguments to boolean only once.

* Fix typos in comments, docs and test names

* Update test_pyparse.py

account for change in string length

* Apply suggestion: splitable -> splittable

Co-Authored-By: Terry Jan Reedy <tjreedy@udel.edu>

* Apply suggestion: splitable -> splittable

Co-Authored-By: Terry Jan Reedy <tjreedy@udel.edu>

* Apply suggestion: Dealloccte -> Deallocate

Co-Authored-By: Terry Jan Reedy <tjreedy@udel.edu>

* Update posixmodule checksum.

* Reverse idlelib changes.

In development mode and in debug build, encoding and errors arguments
are now checked on string encoding and decoding operations. Examples:
open(), str.encode() and bytes.decode().

By default, for best performances, the errors argument is only
checked at the first encoding/decoding error, and the encoding
argument is sometimes ignored for empty strings.

_pyio.IOBase destructor now does nothing if getting the closed
attribute fails to better mimick _io.IOBase finalizer.

Fix destructor _pyio.BytesIO and _pyio.TextIOWrapper: initialize
their _buffer attribute as soon as possible (in the class body),
because it's used by __del__() which calls close().

Adds sys.audit, sys.addaudithook, io.open_code, and associated C APIs.