[docs] What's new item for PEP 526 -- Variable annotations (issue 28109)

[guido at python.org]

http://bugs.python.org/review/28109/diff/18521/Doc/whatsnew/3.6.rst
File Doc/whatsnew/3.6.rst (right):

http://bugs.python.org/review/28109/diff/18521/Doc/whatsnew/3.6.rst#newcode295
Doc/whatsnew/3.6.rst:295: Python interpreter does not attach any
particular meaning to these annotations.
The Python interpreter

(also mention __annotations__?)

http://bugs.python.org/review/28109/diff/18521/Doc/whatsnew/3.6.rst#newcode298
Doc/whatsnew/3.6.rst:298: type metadata for third party tools.
and libraries? (again, __annotations__)

http://bugs.python.org/review/28109/