chore(deps): Update Rust to 1.67.1

[bruceg]

This is mostly clippy fixes of format!("{}", x) into format!("{x}"), with a few dozen if let … else sprinkled in, except for an issue with track_caller in the test utils.

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[tobz]

@bruceg We should hold on this temporarily.

It looks like the change to struct field grouping has the potential to cause deserialization issues with rkyv for data that was serialized with a build based on a prior version of Rust.

I'll have to look into this a little more and see if it effects us and our particular archived structs.

[bruceg]

Possibly related: rust-lang/rust#107440

[tobz]

For posterity, my comment above about holding can be considered resolved.

Chatting with the author of rkyv, we should be entirely protected from the aforementioned struct field ordering change as we use the strict feature flag for rkyv, which ensures a (more) deterministic object layout, regardless of compiler version, and so on.

[bruceg]

Replaced by #16744