Message 351216 - Python tracker

Problem: There are 4 instances of the typo "writeable" in the documentation for the IO library affecting, at least, versions 3.7, 3.8, 3.9, and the latest master of the documentation (https://docs.python.org/[3.7,3.8,3.9]/library/io.html and https://github.com/python/cpython/blob/master/Doc/library/io.rst).  This can cause confusion to the reader.  The instances are under the "BufferedWriter" section (https://docs.python.org/3/library/io.html#io.BufferedWriter) and "BufferedRWPair" section (https://docs.python.org/3.7/library/io.html#io.BufferedRWPair).

Fix: Change all instances of "writeable" to "writable" in the IO library documentation.