Specs clarification: Forbid ClassVar and Final within TypedDict body

[InSyncWithFoo]

• Discussion: What does it mean for a TypedDict to have a ClassVar field?
• Typing council issue: #39: Typing spec update: ClassVar and Final within TypedDict

At runtime, both ClassVar and Final are not recognized as valid qualifiers for TypedDict items:

>>> from typing import TypedDict, ClassVar, Final
>>> class D(TypedDict):
...     a: ClassVar[int]
...
[truncated]
TypeError: typing.ClassVar[int] is not valid as type argument
>>> class D(TypedDict):
...     a: Final[int]
...
[truncated]
TypeError: typing.Final[int] is not valid as type argument

[JelleZijlstra]

I'd prefer to approach this by being precise about where ClassVar and Final are allowed, as opposed to saying something specific to TypedDicts. For example, are they allowed in NamedTuple bodies?

[JelleZijlstra]

I feel this could still be phrased in a more general way, but we can change that later.

[InSyncWithFoo]

Is there anything else need to be done here?