{"ast_node_type":"other","tokens":[{"end":7,"kind":"keyword","start":0,"text":"///"}]}
/// ```
/// assert_eq!(parse_format_exprs("{ident} {} {expr + 42} ").unwrap(), ("{ident} {} {} ".to_owned(), vec![Arg::Placeholder, Arg::Expr("expr + 42".to_owned())]));
pub fn parse_format_exprs(input: &str) -> Result<(String, Vec<Arg>), ()> {