renamed display to output

src/enemies/human.h

@@ -7,7 +7,7 @@ class human final: public enemy_base {
 public:
         human(RNG *rng, const feature enabled_features, const position &pos,
               const int gen_room_num);
-        void print(display *out) override;
+        void print(output *out) override;
         const char *get_race_name() const override;
 };