Document ForwardingAudience

[kezz]

Points to cover

• extend .Single
• how only the terminal methods are overridden
• Use in cross-platform plugins

Example use cases

public class GameTeam implements ForwardingAudience {
  private final List<GamePlayer> players = new ArrayList<>();

  // ....

  @Override
  public @NonNull Iterable<? extends GamePlayer> audiences() {
    return this.players;
  }
}

Migrated from https://github.com/KyoriPowered/adventure-docs/issues/8