Addressing the review comments by Antoine Pitrou for smtplib.py and test_smtplib.py. Review comments by Ezio Melotti for smtplib.rst

This issue can arise with ISPs that redirect all connections on port 25 to
their own (crappy) mail servers.

Merge 3.2: Issue #11699: fix documentation of OptionParser.get_option_group. Patch by Petri Lehtinen

Fix closes Issue11281 - smtplib.STMP gets source_address parameter, which adds the ability to bind to specific source address on a machine with multiple interfaces. Patch by Paulo Scardine.

with the `-m` (or `--match`) option.  This works with all test cases
using the unittest module.  This is useful with long test suites
such as test_io or test_subprocess.

with the `-m` (or `--match`) option.  This works with all test cases
using the unittest module.  This is useful with long test suites
such as test_io or test_subprocess.

fix it. Patch by Petri Lehtinen.

fix it. Patch by Petri Lehtinen.

importlib.import_module eschews a number of issues that __import__ has.
Reviewed by Brett Cannon.  (The docstring of __import__ was already
updated in 3d490c3a019e, for #7397.)