[docs] [issue13424] Add examples for open’s new opener argument

[Roundup Robot]

Roundup Robot added the comment:

New changeset bf1bf3bf3fe2 by Éric Araujo in branch '3.3':
Address reviews for open’s opener argument doc patch (#13424).
http://hg.python.org/cpython/rev/bf1bf3bf3fe2

New changeset 8ca6f4953c4b by Éric Araujo in branch 'default':
Merge #13424 followup from 3.3
http://hg.python.org/cpython/rev/8ca6f4953c4b

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<http://bugs.python.org/issue13424>
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