Fixes rust-lang#95616

…s self

…77, r=compiler-errors

Suggest derivable trait on E0277 error

Closes rust-lang#95099 .

…davidtwco

diagnostics: use correct span for const generics

Fixes rust-lang#95616

Update panic docs to make it clearer when to use panic vs Result

This is based on a question that came up in one of my [error handling office hours](https://twitter.com/yaahc_/status/1506376624509374467?s=20&t=Sp-cEjrx5kpMdNsAGPOo9w) meetings. I had a user who was fairly familiar with error type design, thiserror and anyhow, and rust in general, but who was still confused about when to use panics vs when to use Result and `Error`.

This will also be cross referenced in an error handling FAQ that I will be creating in the https://github.com/rust-lang/project-error-handling repo shortly.

…meters, r=davidtwco

Refactor: remove unused function parameters