Macro try_match_ident_ignore_ascii_case

macro_rules! try_match_ident_ignore_ascii_case {
    ($input:expr, $( $match_body:tt )*) => { ... };
}

A macro to parse an identifier, or return an UnexpectedIdent error otherwise.

FIXME(emilio): The fact that UnexpectedIdent is a SelectorParseError doesn’t make a lot of sense to me.