Change relevant mouse event attributes to floats

[Starbuck5]

In preparation for SDL3, where these attributes are floats. See SDL3 include: https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_events.h.

It would be un-ideal to get these attributes as floats and then cast them to ints before returning them to our users, just throwing away the precision. So we should get ready for the higher precision.

This is not 100% backwards compatible, somebody could be indexing an area with a mousemotion.pos for instance. But I think the vast majority of projects will be unaffected. Especially in Python3, where ints do floating division by default anyways. @ankith26 I'm curious if you think the MOUSEWHEEL change will be too disruptive? I feel like it's more of a change than the pos ones.

[ankith26]

An alternative is to add precise_pos and precise_rel instead. I know adding more attributes is not super elegant, but atleast it's going to be consistent with precise_x and precise_y that we already added kinda recently (and not deprecate it)?

I'm not pushing for this suggestion, just put up a point for discussion with more people

[Starbuck5]

Closing to wait on this