Issue 19300: Swap keyword arguments in open() to make encoding easier to use

>>> print(open.__doc__)
open(file, mode='r', buffering=-1, encoding=None,
     errors=None, newline=None, closefd=True, opener=None) -> file object


It would be handy to use
open('file.txt', 'r', 'utf-8')

instead of
open('file.txt', 'r', encoding='utf-8')