Remove warnings

[DinPX]

There's a warning from unused signal checkpoint_visited(checkpoint_name) in Events.gd, which can be removed by changing # warning-ignore:unused_signal to # warning-ignore-all:unused_signal

The new_name: String argument from func _on_AnimationPlayer_animation_changed in LoadingTransition.gd shows a warning for being unused, changing it to _new_name would remove the warning

The max_speed and acceleration arguments in static func calculate_velocity from Move.gd were already defined so warnings were thrown, changing their names would remove the warnings