Function doc_std 

fn doc_std(
    builder: &Builder<'_>,
    format: DocumentationFormat,
    build_compiler: Compiler,
    target: TargetSelection,
    target_dir: &Path,
    extra_args: &[&str],
    requested_crates: &[String],
) -> Cargo

Prepare a Cargo command for building the documentation for public standard library crates.