[docs] property doc fixes (issue 22174)

[ezio.melotti at gmail.com]

http://bugs.python.org/review/22174/diff/12675/Doc/library/functions.rst
File Doc/library/functions.rst (right):

http://bugs.python.org/review/22174/diff/12675/Doc/library/functions.rst#newcode1111
Doc/library/functions.rst:1111: value.  And *doc* creates a docstring
for the attribute.
Having 3 small and similar sentences separated by a full stop doesn't
sound too well to me, and neither does starting the last with "And".

What about:
"""
*fget*, *fset*, and *fdel* are functions used respectively to get, set,
and delete an attribute value.  *doc* is used to define the docstring of
the attribute.
"""

http://bugs.python.org/review/22174/