Rust

Fix docstring #324

Job	Run time
Check cargo fmt	45s
cargo test (macos)	14m 8s
build with wasm-pack	2m 47s
cargo check	8m 5s
cargo test (macos-aarch64)	14m 7s
Verify MSRV (Min Supported Rust Version)	8m 22s
Verify Vendored Code	56s
cargo test (win64)	1h 4m 50s
cargo test hash collisions (amd64)	17m 21s
clippy	6m 7s
check configs.md and ***_functions.md is up-to-date	3m 8s
check Cargo.toml formatting	3m 7s
cargo doc	4m 29s
cargo test (amd64)	11m 18s
cargo test datafusion-cli (amd64)	3m 55s
cargo test doc (amd64)	16m 23s
cargo examples (amd64)	13m 30s
Run sqllogictest with Postgres runner	3m 42s
cargo test pyarrow (amd64)	3m 1s
verify benchmark results (amd64)	12m 51s
	3h 32m 52s

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