clean potions contants

src/potion.h

@@ -20,6 +20,7 @@ protected:
         potion_type type;
         int remaining_duration;
         position pos;
+        constexpr static const float DROW_POTION_MUL = 1.5f;
 public:
         potion(const potion &p);
         potion(potion &&p);