to 8-bit strings.

#12266: Fix str.capitalize() to correctly uppercase/lowercase titlecased and cased non-letter characters.

Confirm that the prime example is actually correct.  We get so many complaints about a "buggy example" on docs@python, let us hope this cuts them in half at least.

Fix closes issue12698 - make the no_proxy environment variable handling a bit lenient (accomodate spaces in between the items)

Fix closes Issue12183 - Explain the Symlink copy behavior in shutil.copytree. Patch by Petri Lehtinen.

This is a regression introduced in 9211a5d7d0b4, when uses of ST_MTIME
constants were changed to uses of st_mtime attributes.  As diagnosed in
the bug report, this change is not merely stylistic: st_mtime is a
float but ST_MTIME’s resolution is rounded to the seconds, so there was
a mismatch between the values seen by file_util and dep_util which
caused an sdist to be unnecessarily created a second time on an ext4
filesystem.

This patch has been tested by John S. Gruber, who reported the bug.
As this is a simple code revert, I think it’s okay to commit without a
unit test.

This prevents tests from failing when run from a Python installed in a
read-only directory.