refactor(Core): apply clang-tidy modernize-use-override (#3817)

src/server/game/Combat/HostileRefManager.h

@@ -23,7 +23,7 @@ private:
     Unit* iOwner;
 public:
     explicit HostileRefManager(Unit* owner) { iOwner = owner; }
-    ~HostileRefManager();
+    ~HostileRefManager() override;
 
     Unit* GetOwner() { return iOwner; }
 

src/server/game/Combat/ThreatManager.h

@@ -99,13 +99,13 @@ public:
     //=================================================
 
     // Tell our refTo (target) object that we have a link
-    void targetObjectBuildLink();
+    void targetObjectBuildLink() override;
 
     // Tell our refTo (taget) object, that the link is cut
-    void targetObjectDestroyLink();
+    void targetObjectDestroyLink() override;
 
     // Tell our refFrom (source) object, that the link is cut (Target destroyed)
-    void sourceObjectDestroyLink();
+    void sourceObjectDestroyLink() override;
 private:
     // Inform the source, that the status of that reference was changed
     void fireStatusChanged(ThreatRefStatusChangeEvent& threatRefStatusChangeEvent);