Humanize panic handling? about miette

[drmason13]

If it helps, I think this is safe to consider out of scope for Miette.

Having said that, it would be nice to add a mention to the README. Something like:

While you're considering beautiful error outputs for human users of you application...
Have you considered what panic messages look like?
Miette doesn't alter Rust's default panic messages.
You could use a crate like human-panic which does, or even write your own std::panic::set_hook to gain the most flexibility.

I was a bit surprised that the message in human-panic is hardcoded, see: rust-cli/human-panic#54. I wouldn't want to force the exact text they use on users of Miette. Could be a good contribution to human-panic to add a custom message feature (for 2.0.0).