Function rustdoc::doctest::make::check_for_main_and_extern_crate

fn check_for_main_and_extern_crate(
    crate_name: Option<&str>,
    original_source_code: &str,
    everything_else: &str,
    crates: &str,
    edition: Edition,
    can_merge_doctests: bool,
) -> Result<(ParseSourceInfo, bool), FatalError>