[docs] [issue20699] Document that binary IO classes work with bytes-likes objects

[Serhiy Storchaka]

Serhiy Storchaka added the comment:

Oh, I forgot to say my LGTM on your last patch. It LGTM.

But I'm feeling the documentation epic about bytes-like objects is far from the end.

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<http://bugs.python.org/issue20699>
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