Macro bootstrap::doc::tool_doc

macro_rules! tool_doc {
    (
        $tool: ident,
        $should_run: literal,
        $path: literal,
        $(rustc_tool = $rustc_tool:literal, )?
        $(in_tree = $in_tree:literal, )?
        [$($extra_arg: literal),+ $(,)?]
        $(,)?
    ) => { ... };
}