Add _quote and _unquote to http.cookies stub

[UncleGoogle]

Resolves #4895

[srittau]

Thanks.

[Akuli]

If the str variable is None, then these functions return it unchanged, but otherwise these never return None. Maybe we could do something like this to fix that?

[Akuli]

Suggested change

	def _quote(str: str) -> str: ...
	def _unquote(str: str) -> str: ...
	@overload
	def _quote(str: None) -> None: ...
	@overload
	def _quote(str: str) -> str: ...
	@overload
	def _unquote(str: None) -> None: ...
	@overload
	def _unquote(str: str) -> str: ...

[Akuli]

I guess I might as well make a new PR to fix this.

[UncleGoogle]

Thanks, I didn't noticed.