[docs] simplify int() signature docs (issue 16036)

[storchaka at gmail.com]

http://bugs.python.org/review/16036/diff/6073/Doc/library/functions.rst
File Doc/library/functions.rst (right):

http://bugs.python.org/review/16036/diff/6073/Doc/library/functions.rst#newcode637
Doc/library/functions.rst:637: For floating point numbers, this
truncates towards zero.
I don't know if it worth to mention specifically such details. Floating
pointer numbers truncated first and then __int__() method called for
result.

http://bugs.python.org/review/16036/