{"ast_node_type":"function","tokens":[{"end":87,"kind":"keyword","start":0,"text":"let"}]}
    let (tags, text) = extract_tags(r#"<tag fn>fn <tag>main</tag>() {}</tag>"#, "tag");
fn test_extract_tags() {
    let actual = tags.into_iter().map(|(range, attr)| (&text[range], attr)).collect::<Vec<_>>();