[docs] [issue25701] Document that tp_setattro and tp_setattr are used for deleting attributes

Serhiy Storchaka added the comment: I think the conclusion of Python_Dev discussion is that it is not worth to deprecate this behavior in the code. Current behavior of PyObject_SetAttr and PySequence_SetItem should be documented with a deprecation notice. ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue25701> _______________________________________