v21.1 Changing Trainers 1.2.5

This resource was made to make a trainer's party potentially more flexible depending on what's being desired. For example, you might have a trainer you gave two Pokémon slots, but you have three mons you'd like to give to that trainer as you think they fit. Let's say Rattata, Pidgey and Pikachu. Perhaps you can make it so that while slot 2 is always a Pikachu, slot 1 could either be Rattata or Pidgey.

Important Note: It's changingTrainerBattle(...). No .start is needed.