Improve PalPark table docs slightly.
Improve PalPark table docs slightly.

Also add format='identifier' to PalParkArea.identifier, which was
causing a failure in test_schema.

veekun/pokedex,DaMouse404/pokedex,RK905/pokedex-1,xfix/pokedex,veekun/pokedex,mschex1/pokedex