Rust

Minor: clean up the code based on Clippy #20649

Job	Run time
cargo test (mac)	20m 59s
build with wasm-pack	2m 7s
cargo check	2m 27s
Verify Vendored Code	46s
cargo test (win64)	28m 20s
Check cargo fmt	36s
Verify MSRV	6m 15s
cargo test (amd64)	8m 35s
cargo examples (amd64)	6m 7s
check Cargo.toml formatting	1m 15s
clippy	4m 10s
check configs.md is up-to-date	2m 12s
cargo test hash collisions (amd64)	8m 43s
cargo doc	4m 26s
cargo test datafusion-cli (amd64)	2m 53s
cargo test doc (amd64)	9m 55s
Run sqllogictest with Postgres runner	4m 16s
cargo test pyarrow (amd64)	2m 12s
verify benchmark results (amd64)	9m 24s
	2h 5m 38s

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