small clippy lint for Rust 1.68

[Pat-Lafon]

Only a small change for the new Rust release.

I'll note that there is an additional future-incompat warning that we hit because of the current version of lalrpop. rust-lang/rust#103418 lalrpop/lalrpop#701

In one sense, it's kind of a non-issue because it doesn't hold up the ci and I think this can only become a hard error over an edition change. On the other hand, it's a little disconcerting if lalrpop isn't getting much attention from the maintainers these days.

I would expect that a (new?) maintainer will arise who can cut a new lalrpop release which will resolve this issue. Otherwise this could motivate a switch in parsers.

[Pat-Lafon]

Speaking of being unmaintained, apparently actions-rs is suffering from this issue. Here there seems to be a good amount of movement to dtolnay/rust-toolchain like with rust-lang/regex@bbb9dac so I feel reasonably confident in switching over.

[sampsyo]

Very nice; many thanks, as always!

It's really too bad about lalrpop; there are just not that many good options for solid parser generators in the ecosystem (is pest the only viable alternative? There's Chumsky but that's a very different style).

And thanks for switching to rust-toolchain; looks great!

[Pat-Lafon]

I've explored using https://github.com/hydro-project/rust-sitter to leverage the tree-sitter ecosystem but it doesn't have the same kind of maturity yet(being built into the proc-macro attribute system of Rust does have a certain appeal/benefits).