Missing doc on exact usage of this crate

[matthiasbeyer]

Choose one: is this a 🐛 bug report

Missing docs are a bug, right? :laughing:

So what I am missing is just a short explanation where to call the setup_panic!() macro, actually: Inside main? Outside of any function? Just a bit of confusion on my end because the docs do not show where to put the call.

Thanks for this nice crate!