Issue #27125: Merge typo fixes from 3.5

Also merge changes from Issue #27117; no actual code changes to 3.6.

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

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

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

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

diff --cc Lib/collections/__init__.py
Simple merge

diff --cc Lib/tkinter/tix.py
Simple merge

diff --cc Objects/object.c
Simple merge

diff --cc README
Simple merge