make the right items drop with kill counters

src/ship/drops/rare_drop_table.rs

@@ -103,7 +103,13 @@ impl RareDropTable {
                     grind: 0,
                     attrs: self.attribute_table.generate_rare_attributes(map_area, rng),
                     tekked: false,
-                    kills: None,
+                    kills: {
+                        if weapon.has_counter() {
+                            Some(0)
+                        } else {
+                            None
+                        }
+                    },
                 })
 
             },
@@ -126,7 +132,13 @@ impl RareDropTable {
                 ItemDropType::Unit(Unit {
                     unit,
                     modifier: None,
-                    kills: None,
+                    kills: {
+                        if unit.has_counter() {
+                            Some(0)
+                        } else {
+                            None
+                        }
+                    },
                 })
             },
             RareDropItem::Tool(tool) => {