Merge #20592: doc: update wtxidrelay documentation per BIP339

4b7b58b Update net_processing WTXID documentation per BIP339 (Jon Atack)

Pull request description:

  BIP339 currently states:

  *The wtxidrelay message MUST be sent in response to a version message from a peer whose protocol version is >= 70016 and prior to sending a verack. A wtxidrelay message received after a verack message MUST be ignored or treated as invalid.*

ACKs for top commit:
  MarcoFalke:
    ACK 4b7b58b
  practicalswift:
    ACK 4b7b58b
  RiccardoMasutti:
    ACK 4b7b58b

Tree-SHA512: 58ca6b197618cc73c70aa5de0a2d9d89a68b4cad9d5a708278ef17a9d6854d4362bcc384b6d29696642924977204a8fc120b31e91e2d97b6072b7b0d41c9f2dc

Author: MarcoFalke

src/net_processing.cpp

@@ -2488,8 +2488,8 @@ void PeerManager::ProcessMessage(CNode& pfrom, const std::string& msg_type, CDat
         return;
     }
 
-    // Feature negotiation of wtxidrelay should happen between VERSION and
-    // VERACK, to avoid relay problems from switching after a connection is up
+    // Feature negotiation of wtxidrelay must happen between VERSION and VERACK
+    // to avoid relay problems from switching after a connection is up.
     if (msg_type == NetMsgType::WTXIDRELAY) {
         if (pfrom.fSuccessfullyConnected) {
             // Disconnect peers that send wtxidrelay message after VERACK; this