kick for self-attacking (#430)

* fix(combat): kick for self-attacking

* chore(combat): fix the duplication of the word client

* chore(pumpkin/src/net/packet/play.rs#Player/handle_interact): remove useless parens

* fix(combat): compare entity IDs, not actual objects

* chore(pumpkin/src/net/packet/play): `cargo fmt`

pumpkin/src/net/packet/play.rs

@@ -556,10 +556,16 @@ impl Player {
                     return;
                 };
                 if victim.living_entity.health.load() <= 0.0 {
-                    // you can trigger this from a non-modded / innocent client client,
+                    // you can trigger this from a non-modded / innocent client,
                     // so we shouldn't kick the player
                     return;
                 }
+                if victim.entity_id() == self.entity_id() {
+                    // this, however, can't be triggered from a non-modded client.
+                    self.kick(TextComponent::text("You can't attack yourself"))
+                        .await;
+                    return;
+                }
                 self.attack(&victim).await;
             }
             ActionType::Interact | ActionType::InteractAt => {