doc: Remove -whitelistforcerelay from comment

Instead, permission flags should be used. For example
-whitelist=forcerelay@127.0.0.1

src/net_processing.cpp

@@ -4387,9 +4387,9 @@ bool PeerLogicValidation::SendMessages(CNode* pto)
         //
         // Message: feefilter
         //
-        // We don't want white listed peers to filter txs to us if we have -whitelistforcerelay
         if (pto->m_tx_relay != nullptr && pto->nVersion >= FEEFILTER_VERSION && gArgs.GetBoolArg("-feefilter", DEFAULT_FEEFILTER) &&
-            !pto->HasPermission(PF_FORCERELAY)) {
+            !pto->HasPermission(PF_FORCERELAY) // peers with the forcerelay permission should not filter txs to us
+        ) {
             CAmount currentFilter = m_mempool.GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFeePerK();
             int64_t timeNow = GetTimeMicros();
             if (timeNow > pto->m_tx_relay->nextSendTimeFeeFilter) {