[docs] [issue15034] Document best practices for exceptions

Irit Katriel added the comment: There are examples in the tutorial where super().__init__ is not called, like here: https://docs.python.org/3/tutorial/errors.html#user-defined-exceptions ---------- nosy: +iritkatriel versions: +Python 3.10, Python 3.8, Python 3.9 -Python 2.7, Python 3.2, Python 3.3 _______________________________________ Python tracker https://bugs.python.org/issue15034 _______________________________________