Export Query type

[Dreamsorcerer]

In aiohttp we define params which is simply passed to URL.with_query(). We should have this parameter typed to allow the same things, but the type is rather complex:

yarl/yarl/__init__.pyi

Lines 18 to 22 in efea830

	_SimpleQuery = Union[str, int, float]
	_QueryVariable = Union[_SimpleQuery, Sequence[_SimpleQuery]]
	_Query = Union[
	None, str, Mapping[str, _QueryVariable], Sequence[Tuple[str, _QueryVariable]]
	]

Therefore, it'd be useful to export this type from yarl in order to be reused.

[bdraco]

I think this should be a bit easier to make work now