[docs] Documentation regressions from adding subprocess.run() (issue 24420)

[berker.peksag at gmail.com]

http://bugs.python.org/review/24420/diff/15059/Doc/library/subprocess.rst
File Doc/library/subprocess.rst (right):

http://bugs.python.org/review/24420/diff/15059/Doc/library/subprocess.rst#newcode880
Doc/library/subprocess.rst:880: .. function:: check_output(args, *[,
input], stdin=None, stderr=None, shell=False, universal_newlines=False,
timeout=None)
I think we can now remove *input* from the signature.

The following paragraph makes the *input* parameter's presence
redundant:

+   The arguments shown above are merely the most common ones.
+   The full function signature is largely the same as that of
:func:`run` -
+   most arguments are passed directly through to that interface.
+   The differences are that explicitly passing ``input=None`` is not
+   supported, and that *stdout* is not permitted as an argument, as
+   it is used internally to collect the output from the subprocess.

Also, without ``[, input],``, the signature looks more readable to me.

http://bugs.python.org/review/24420/