Function type_specifier 

pub fn type_specifier<'tokens, 'src: 'tokens>(
    node: impl Parser<'tokens, InputType<'tokens, 'src>, Node<'src>, RichExtra<'tokens, 'src>> + Clone,
) -> impl Parser<'tokens, InputType<'tokens, 'src>, Spanned<TypeSpecifier<'src>>, RichExtra<'tokens, 'src>> + Clone