Multi shotgun fix (#8460)

* Multi-barrel shotgun fix

* multi-recoil support

* @Nullable for everything

core/src/mindustry/entities/pattern/ShootMulti.java

@@ -1,5 +1,7 @@
 package mindustry.entities.pattern;
 
+import arc.util.*;
+
 public class ShootMulti extends ShootPattern{
     public ShootPattern source;
     public ShootPattern[] dest = {};
@@ -25,7 +27,7 @@ public class ShootMulti extends ShootPattern{
     }
 
     @Override
-    public void shoot(int totalShots, BulletHandler handler){
+    public void shoot(int totalShots, BulletHandler handler, @Nullable Runnable barrelIncrementer){
         source.shoot(totalShots, (x, y, rotation, delay, move) -> {
             for(var pattern : dest){
                 pattern.shoot(totalShots, (x2, y2, rot2, delay2, mover) -> {
@@ -35,6 +37,6 @@ public class ShootMulti extends ShootPattern{
                     });
                 });
             }
-        });
+        }, barrelIncrementer);
     }
 }