fix: add '__in!' as suffix to keep in url query strings

[chackley42]

No description provided.

[joshorr]

I think what you have here is good enough, just add a unit test.

Future Consideration/Notes:

I think we may want to have a new formatting option, a not suffix value and default it to !.

That way we can do this:

if someone had this query value: {'hello!': ['1', '2']} , I think I would expect it to produce a ?hello__in!=1,2