Ignore specific error for whole file #11027

It's possible to either # type: ignore for a whole file or # type: ignore[specific] on a line. A combination of both would be useful.

This script:

def test(input):
	pass

yields:

error: Function is missing a type annotation [no-untyped-def]

This script:

# type: ignore[assignment]

def test(input):
	pass

yields:

Success: no issues found in 1 source file

... while I think it would make more sense for the no-untyped-def error to still be raised, as we're only trying to ignore assignment errors.