TypedDict w/ extra items accepts `str` key but not `LiteralString`

[yangdanny97]

from typing import TypedDict, LiteralString

class TD(TypedDict, extra_items=str):
    ...
def test(x: TD, k1: LiteralString, k2: str):
    x[k1] # error
    x[k2] # no error

https://pyright-play.net/?strict=true&code=GYJw9gtgBALgngBwJYDsDmUkQWEMoAqiApgCYAiSAxjADRQAySMxIAhgDYDKMIqaAKAFUObAM5jC5ABREEZSjXrEAHrzYB9ZsQhiAvGN4BKAFwCoFqADobA0sWCxih6SpNT6AawCM7pi3ZuXn4vACZ3QxBTc0sVAG0fAF0Yi3jPUMSgA

[erictraut]

Thanks for the bug report. Yeah, I agree that should work.