Rust

Migrate documentation for `regr*` aggregate functions to code #33705

Job	Run time
Check cargo fmt	44s
cargo check	10m 53s
build with wasm-pack	2m 40s
cargo test (macos)	11m 43s
cargo test (macos-aarch64)	10m 27s
Verify MSRV (Min Supported Rust Version)	8m 18s
Verify Vendored Code	49s
cargo test (win64)	58m 3s
cargo examples (amd64)	13m 49s
cargo doc	3m 54s
cargo test hash collisions (amd64)	17m 29s
cargo test (amd64)	11m 4s
clippy	5m 55s
cargo test datafusion-cli (amd64)	4m 9s
Run sqllogictest with Postgres runner	3m 33s
cargo test pyarrow (amd64)	2m 50s
verify benchmark results (amd64)	12m 22s
cargo test doc (amd64)	15m 6s
check Cargo.toml formatting	2m 54s
check configs.md and ***_functions.md is up-to-date	3m 7s
	3h 19m 49s

Provide feedback