Rename crate::events to crate::messages

Bevy 0.17 introduces this idea of "Messages" which mostly replace the
previous usage of "Events." The old events still exist, but are meant
more for targetted actions -- something happening and immediately
triggering a function call on an observer.

src/objects.rs

@@ -23,7 +23,7 @@ use bevy_rapier2d::prelude::{ActiveCollisionTypes, ActiveEvents, Collider, Senso
 use crate::{
     AngularVelocity, GameAssets, GameState, Lives,
     config::{ASTEROID_LIFETIME, DEBRIS_LIFETIME, SHIP_FIRE_RATE},
-    events::{AsteroidDestroy, BulletDestroy, ShipDestroy, SpawnAsteroid},
+    messages::{AsteroidDestroy, BulletDestroy, ShipDestroy, SpawnAsteroid},
     machinery::{Lifetime, Sparkler},
     physics::{Velocity, Wrapping},
 };