Use `ParseError::or` when reporting a failure from `line_ending`

[Lucretiel]

Currently, when line_ending fails, it returns ErrorKind::CrLf, same as crlf. In the interest of maximally helpful error reporting, I propose that line_ending instead return:

E::or(
    E::from_char(input.clone(), '\n'),
    E::from_error_kind(input, ErrorKind::CrLf),
)