[docs] [issue26224] Add "version added" for documentation of asyncio.timeout for documentation of python 3.4, 3.5, 3.6

[Berker Peksag]

Changes by Berker Peksag <berker.peksag at gmail.com>:


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type:  -> behavior

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue26224>
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