Core: Fix many "errors"/warnings and coding style (3)

Game

Errors were found using Cppcheck, open-source static analysis tool

src/server/game/AI/SmartScripts/SmartScriptMgr.cpp

@@ -913,7 +913,7 @@ bool SmartAIMgr::IsEventValid(SmartScriptHolder& e)
     return true;
 }
 
-bool SmartAIMgr::IsTextValid(SmartScriptHolder const& e, uint32 id)
+/*bool SmartAIMgr::IsTextValid(SmartScriptHolder const& e, uint32 id) // unused
 {
     bool error = false;
     uint32 entry = 0;
@@ -938,4 +938,4 @@ bool SmartAIMgr::IsTextValid(SmartScriptHolder const& e, uint32 id)
         return false;
     }
     return true;
-}
+}*/