declare more precise getClass* return types

[staabm]

[ondrejmirtes]

Yeah, still a BC break, we have to wait for 2.0 if we find it valuable.

[staabm]

agree. thx for the review.

[staabm]

what do you think about adding these PRs to a separate milestone, so they won't be forgotten when we do the next major version?

[ondrejmirtes]

That's not necessary, I've got a private todolist with 50 items already, it's not gonna get lost.