`EMPTY` rect has suboptimal values about bevy

[viridia]

I want to point out that in three.js the initial values are +INFINITY and -INFINITY, not FLOAT_MAX and FLOAT_MIN. For integer rects, there's no infinity, so MAX/MIN are the correct values.

This works because min(value, INFINITY) == value for all finite numbers. The converse is true for max/-INFINITY.

In practice, of course, no one is going to actually use a rectangle of either infinite or max size in rendering. The only purpose for having this is as a starting point for geometrical calculations.

Both Box2 and Box3 (the 3D version of Box) in three.js use this construction.

[viridia]

One more comment: A classic use case here is finding a bounding box of a set of points. By setting the initial rectangle to negative infinite size, we can then call union_point(pt) for each point in the set, without needing to treat the first point in the list as a special case.

[Olle-Lukowski]

I could go ahead and change this, I assume it is just updating the implementation of rect and updating docs accordingly that is needed?