The test needs to be skipped if unicodedata is either part of the
main binary (a repackaging of cpython on Windows?) or has python
source (pypy?).  PEP 3147 makes __file__ point to the .py source,
so we need to change the extension check from looking for the
old .pyc/.pyo to just looking for .py.

Note that this skip should never trigger on CPython itself, so
one could argue it should be dropped instead.  But since it exists,
why risk breaking someone else's python.

Python3 does not have the bug covered by the issue.

derived from sr_rs@latin.

Original patch by Georg Brandl.

All Python-specific styling is now in the theme anyway.

We don't want to go into a full explanation of scopes at this point in the
tutorial, so we just mention that the loop creates or overwrites a persistent
variable while the listcomp doesn't.  Not mentioning this would lead someone
to incorrectly assume loops and listcomps were *completely* equivalent, which
would confuse them later.

Original patch by Rose Ames, tweaked to remove the word 'scope'.

Patch by Francis MB.

Move Doc/tools/sphinxext content to Doc/tools, there is no need for the nested subdirectory anymore.

calls that were cancelled.

because _read_null() cannot be used on AIX. On AIX, reading from NULL is
allowed: the first page of memory is a mapped read-only on AIX.

os.posix_fallocate() because their prototypes in system headers are wrong.