New attack function for single character in characters.h, need implementation (example in shade.h)

src/shade.h

@@ -10,6 +10,7 @@ public:
                               character_list &chlist) override;
         virtual result get_hit(const enum race &race, const int atk,
                                const fraction hit_rate) override;
+        virtual result attack(const direction dir, character *ch) override;
 };
 
 #endif