replace Stepper::min/max with 'with_range'

[cmyr]

I think these two methods are slightly too generally named, and I would like to be consistent with the new method on Slider.

[luleyleo]

I've just started to get this done, but renaming it to with_range feels kind of weird when the next line is step(..) and not with_step(..).
Currently there are many methods not using the builder style naming with_ and it feels like this change would make the naming less consistent.
I think it would be best to first decide whether to use builder style naming for all of none of the methods. My favorite would be naming it just range(.., ..) as the with_ prefix really only makes sense when there are equivalent none builder methods on the same struct.

[cmyr]

yep, with_step is also welcome.

My current feeling is that builder-style methods that take an argument should be with_. I have two main concerns: one is just consistency, and having a clear convention for naming, and the other is that overly generic method names are likely to collide with other things (for instance, there's a problem with colliding with derived lens names)— but also specifically that with WidgetExt if we have overly generic method names and those are auto-impl'd for a bunch of types, it becomes quite likely there will be a collision on some type, which will cause hard to diagnose compiler errors.