Rust

improve detection of file types #87

Job	Run time
test	1m 33s
build (x86_64-unknown-linux-musl, ubuntu-latest)	1m 47s
build (aarch64-apple-darwin, macos-latest)	1m 30s
build (x86_64-pc-windows-msvc, windows-latest)	3m 33s
build (x86_64-apple-darwin, macos-latest)	2m 12s
	10m 35s

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