Issue 10534, difflib: tweak doc; test new SequenceMatcher instance attributes; avoid unneeded lists of SM.b2j keys and items in .__chain_b. Do not backport.

or `python -m test` should be used instead.

socket timeout of 30 when it checks for resource.  Explicit overrding (like
setting the 10) wont exhibit consistent behavior when tests are outside context
manager. So, settting it 30.

Patch by Simon Cross, crasher test code by Martin von Löwis.

Also includes doc updates mentioning that these entries may not
be retrievable via getgrnam and getgrgid.

Patch by Bobby Impollonia.

OSError exception when The OS had been told to ignore SIGCLD in our process
or otherwise not wait for exiting child processes.

Passing the port as a string value works fine in regular mode, but
if you turned debug on it would throw an error trying to print the
port number, which is surprising and confusing.

Issue #7213: Change the close_fds default on Windows to better match the new
default on POSIX.  True when possible (False if stdin/stdout/stderr are
supplied).

Update the documentation to reflect all of the above.

Thanks to Garrett Cooper for the fix.

Also document the use of three-tuples if control of the charset
and language is desired.