{"ast_node_type":"variable","tokens":[{"end":58,"kind":"keyword","start":0,"text":"let"}]}
    let mut new_stream = Vec::with_capacity(stream.len());
fn normalize<'a>(MdStream(stream): MdStream<'a>, linkdefs: &mut Vec<MdTree<'a>>) -> MdStream<'a> {
    let new_defs = stream.iter().filter(|tt| matches!(tt, MdTree::LinkDef { .. }));