Macro mentat_parser_utils::def_matches_namespaced_keyword

macro_rules! def_matches_namespaced_keyword {
    ( $parser: ident, $name: ident, $input_namespace: expr, $input_name: expr ) => { ... };
}

Generate a satisfy expression that matches a Keyword value with the given namespace and name.

We do this rather than using combine::token to save allocations.