Lint error with toolchain version 1.83

[changhc]

The stable channel had a new release 1.83 on 28 Nov. The new toolchain version brings some changes to rustfmt and clippy, and this breaks the CI lint check for my PR because the workflow uses the stable channel. I quickly made some changes in a branch (#1561) to fix this, but meanwhile I'd like to know if the team prefers to keep using stable or to pin the repo to a specific toolchain version. Maybe we should also add a rust-toolchain.toml file to make this explicit, even if the team decides to stick to stable.

Versions in the new stable toolchain:

$ cargo clippy --version
clippy 0.1.83 (90b35a6 2024-11-26)
$ cargo fmt --version      
rustfmt 1.8.0-stable (90b35a6239 2024-11-26)
$ rustc -V                  
rustc 1.83.0 (90b35a623 2024-11-26)

[davidhewitt]

I think leaving it as stable is fine, I think there is a way to pin the workflow but I don't know if dependabot respects that; might get stale.