MRG: misc Rust updates to core #5559

Job	Run time
Check	34s
coverage	9m 55s
Lints (beta)	12s
Lints (stable)	7s
test (beta)	1m 42s
test (stable)	1m 35s
test_all_features	13m 22s
test (windows)	3m 9s
test (macos)	1m 19s
Run tests under wasm32-wasi	1m 14s
Check if wasm-pack builds a valid package for the sourmash crate	1m 20s
Check if cbindgen runs cleanly for generating the C headers	8m 15s
minimum_rust_version	8m 7s
Publish (dry-run)	5m 59s
	56m 50s

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