fix(Core/Misc): all GCC warnings (#3457)

src/server/game/DungeonFinding/LFGGroupData.cpp

@@ -29,10 +29,11 @@ void LfgGroupData::SetState(LfgState state)
         case LFG_STATE_NONE:
             m_Dungeon = 0;
             m_KicksLeft = LFG_GROUP_MAX_KICKS;
+            [[fallthrough]];
         case LFG_STATE_FINISHED_DUNGEON:
         case LFG_STATE_DUNGEON:
             m_OldState = state;
-            // No break on purpose
+            [[fallthrough]];
         default:
             m_State = state;
     }