Parser: Shove token info into lily_parser_tok_table.h

This setup is much better than before. For one, it's easy to see what values
go to what tokens (versus 'add a 0 here and cross fingers'). This is less
about making it easier to extend (since I don't think there will be many more
new tokens), but about making it easier to understand.

This is nice because I can change token stuff in parser now without feeling
like I accidentally broke something (or debugging a random token messup).
Parser: Use new token table to simply expression.