[docs] re.VERBOSE whitespace behavior not completely documented (issue 15606)

[ezio.melotti at gmail.com]

http://bugs.python.org/review/15606/diff/5718/Doc/library/re.rst
File Doc/library/re.rst (right):

http://bugs.python.org/review/15606/diff/5718/Doc/library/re.rst#newcode540
Doc/library/re.rst:540: extension construct (so, for example,
``(?P<a_or_b> a | b)`` is a
Reading this it seems to me that ``( ?:`` is allowed.  Maybe saying
something like "within tokens like ``(?:`` or ``(?P<...>``" is better.

http://bugs.python.org/review/15606/diff/5718/Doc/library/re.rst#newcode546
Doc/library/re.rst:546: the leftmost such ``'#'`` through the end of the
line are ignored.
I find this paragraph a bit confusing, and would rephrase it to
something like:
"""
All the text after and including the ``'#'`` character is considered as
comment and ignored, unless the ``'#'`` is in a character class or it's
preceded by an unescaped backslash.
"""

http://bugs.python.org/review/15606/