in helpers/mdbook-exercise-linker/src/main.rs [55:67]
fn handle_supports(pre: &dyn Preprocessor, sub_args: &ArgMatches) -> ! {
let renderer = sub_args
.get_one::<String>("renderer")
.expect("Required argument");
let supported = pre.supports_renderer(renderer);
// Signal whether the renderer is supported by exiting with 1 or 0.
if supported {
process::exit(0);
} else {
process::exit(1);
}
}