Update pydoc topics.
Issue #20571: skip test_readline() of test_codecs for Windows code page 65001.
The decoder does not support partial decoding yet for this code page.
#20677: fix typo in enum docs.  Patch by Saimadhav Heblikar.
Issue #20637: Key-sharing now also works for instance dictionaries of subclasses.  Patch by Peter Ingebretson.
whatsnew: ExtensionFileLoader.get_filename.

Also reflow mmap paragraph.
whatsnew: textwrap.shorten.

Also add the missing TextWrapper.shorten method doc.
whatsnew: hashlib.hash.name is now public and returns lowercase always.
whatsnew: devnull fileno/close/closed.
Fix wording in news entry.
whatsnew: pyvenv --copies option.

Also added the missing documentation for new new option.
Issue #20743: Fix a reference leak in test_tcl.
Issue #20743: Fix a reference leak in test_tcl.
Issue #20750, Enable roundtrip tests for new 5-tuple untokenize. The
constructed examples and all but 7 of the test/test_*.py files (run with -ucpu)
pass. Remove those that fail the new test from the selection list.
Patch partly based on patches by G. Brandl (#8478) and G. Rees (#12691).
Merge with 3.3, #20750
whatsnew: unittest drops references to successful tests.
whatsnew: unittest uses argparse now.
whatsnew: threading.main_thread, os.urandom persistent handle, sunau.open with.
Fix wording in NEWS entry.
Issue #9974: When untokenizing, use row info to insert backslash+newline.
Original patches by A. Kuchling and G. Rees (#12691).
Merge with 3.3