Add turret ammo capacity to the in-game help (#9777)

* Add turret ammo capacity to the in-game help

* Rename max shots to ammo capacity

* Rename ammo multipier to ammo per item

core/src/mindustry/world/blocks/defense/turrets/ItemTurret.java

@@ -49,6 +49,7 @@ public class ItemTurret extends Turret{
 
         stats.remove(Stat.itemCapacity);
         stats.add(Stat.ammo, StatValues.ammo(ammoTypes));
+        stats.add(Stat.ammoCapacity, maxAmmo / ammoPerShot, StatUnit.shots);
     }
 
     @Override