♻️ Fix inconsistent monster id variables

The monster id naming convention was inconsistent with several names being used: i, mid, mon, mi, monsterId

This chanage normalises all names to monsterId

Source/monster.h

@@ -275,7 +275,7 @@ extern bool sgbSaveSoundOn;
 void PrepareUniqueMonst(Monster &monster, int uniqindex, int miniontype, int bosspacksize, const UniqueMonsterData &uniqueMonsterData);
 void InitLevelMonsters();
 void GetLevelMTypes();
-void InitMonsterGFX(int monst);
+void InitMonsterGFX(int monsterTypeIndex);
 void monster_some_crypt();
 void InitGolems();
 void InitMonsters();
@@ -284,22 +284,22 @@ int AddMonster(Point position, Direction dir, int mtype, bool inMap);
 void AddDoppelganger(Monster &monster);
 bool M_Talker(const Monster &monster);
 void M_StartStand(Monster &monster, Direction md);
-void M_ClearSquares(int i);
-void M_GetKnockback(int i);
-void M_StartHit(int i, int dam);
-void M_StartHit(int i, int pnum, int dam);
-void StartMonsterDeath(int mid, int pnum, bool sendmsg);
-void M_StartKill(int i, int pnum);
-void M_SyncStartKill(int i, Point position, int pnum);
-void M_UpdateLeader(int i);
+void M_ClearSquares(int monsterId);
+void M_GetKnockback(int monsterId);
+void M_StartHit(int monsterId, int dam);
+void M_StartHit(int monsterId, int pnum, int dam);
+void StartMonsterDeath(int monsterId, int pnum, bool sendmsg);
+void M_StartKill(int monsterId, int pnum);
+void M_SyncStartKill(int monsterId, Point position, int pnum);
+void M_UpdateLeader(int monsterId);
 void DoEnding();
 void PrepDoEnding();
-void M_WalkDir(int i, Direction md);
-void GolumAi(int i);
+void M_WalkDir(int monsterId, Direction md);
+void GolumAi(int monsterId);
 void DeleteMonsterList();
 void ProcessMonsters();
 void FreeMonsters();
-bool DirOK(int i, Direction mdir);
+bool DirOK(int monsterId, Direction mdir);
 bool PosOkMissile(Point position);
 bool LineClearMissile(Point startPoint, Point endPoint);
 bool LineClear(const std::function<bool(Point)> &clear, Point startPoint, Point endPoint);
@@ -319,7 +319,7 @@ bool IsGoat(_monster_id mt);
 bool SpawnSkeleton(int ii, Point position);
 int PreSpawnSkeleton();
 void TalktoMonster(Monster &monster);
-void SpawnGolem(int i, Point position, Missile &missile);
+void SpawnGolem(int id, Point position, Missile &missile);
 bool CanTalkToMonst(const Monster &monster);
 int encode_enemy(Monster &monster);
 void decode_enemy(Monster &monster, int enemyId);