Core: Append single character to stream as character, not as a string

src/server/game/Pools/PoolMgr.cpp

@@ -790,7 +790,7 @@ void PoolMgr::LoadFromDB()
                         std::ostringstream ss;
                         ss<< "The pool(s) ";
                         for (std::set<uint32>::const_iterator itr=checkedPools.begin(); itr != checkedPools.end(); ++itr)
-                            ss << *itr << " ";
+                            ss << *itr << ' ';
                         ss << "create(s) a circular reference, which can cause the server to freeze.\nRemoving the last link between mother pool "
                             << poolItr->first << " and child pool " << poolItr->second;
                         sLog->outErrorDb("%s", ss.str().c_str());