[docs] [issue11468] Improve unittest basic example in the doc

[Ezio Melotti]

Ezio Melotti added the comment:

Given that this is a basic example, it's not necessary to introduce both the forms of assertRaises.
I personally find the context manager form more readable, and I prefer it to the regular one even if it takes two lines instead of one.

----------

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue11468>
_______________________________________