{"ast_node_type":"variable","tokens":[{"end":93,"kind":"keyword","start":0,"text":"let"}]}
    let mut broken_link_callback = |link: BrokenLink<'md>| Some((link.reference, "".into()));
fn parse_links<'md>(doc: &'md str) -> Vec<Box<str>> {
    let mut event_iter = Parser::new_with_broken_link_callback(