Function render_help_styled 

pub fn render_help_styled(
    spec: &Spec,
    cmd: &SpecCommand,
    long: bool,
    style: Style,
) -> String

Render a terminal help page with an explicit colour policy.

Runs nothing: choices run= is described as where the values come from. A program showing its own help while it runs wants render_runtime_help, which lists them.