pub fn escaped_string<I>(
must_esc: &'static [char],
esc: &Escape,
) -> impl Parser<I, Output = String>where
I: RangeStream<Token = char>,
<I as StreamOnce>::Error: ParseError<<I as StreamOnce>::Token, <I as StreamOnce>::Range, <I as StreamOnce>::Position>,
<I as StreamOnce>::Range: Range,