Add Docs and Examples and helper methods to `PhysicalSortExpr` #32574

Job	Run time
build with wasm-pack	2m 32s
cargo test (win64)	48m 31s
Check cargo fmt	36s
cargo check	6m 41s
cargo test (macos)	13m 50s
cargo test (macos-aarch64)	11m 18s
Verify MSRV (Min Supported Rust Version)	7m 19s
Verify Vendored Code	43s
cargo test datafusion-cli (amd64)	3m 58s
cargo examples (amd64)	13m 34s
clippy	5m 17s
cargo doc	4m 13s
cargo test (amd64)	9m 59s
cargo test doc (amd64)	15m 16s
Run sqllogictest with Postgres runner	3m 46s
cargo test pyarrow (amd64)	2m 56s
verify benchmark results (amd64)	12m 49s
check Cargo.toml formatting	3m 6s
cargo test hash collisions (amd64)	15m 2s
check configs.md is up-to-date	3m 18s
	3h 4m 44s

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