Bounce message corrections

On IRC it is confusing when an XMPP user "corrects" a message, but on
the other side a new message is sent. To prevent spam and confusion, do
not allow message corrections at all, and instead return an error if
attempted.

Fixes: #3436
Fixes: #3480

src/xmpp/biboumi_component.cpp

@@ -295,6 +295,15 @@ void BiboumiComponent::handle_message(const Stanza& stanza)
                               error_type, error_name, error_text);
     });
   const XmlNode* body = stanza.get_child("body", COMPONENT_NS);
+  const XmlNode* replace = stanza.get_child("replace", MESSAGE_CORRECT_NS);
+
+  if (replace)
+  {
+    error_type = "cancel";
+    error_name = "feature-not-implemented";
+    error_text = "This room is mapped from IRC, which does not support message correction.";
+    return;
+  }
 
   try {                         // catch IRCNotConnected exceptions
   if (type == "groupchat" && iid.type == Iid::Type::Channel)

src/xmpp/xmpp_component.hpp

@@ -39,6 +39,7 @@
 #define STABLE_ID_NS     "urn:xmpp:sid:0"
 #define STABLE_MUC_ID_NS "http://jabber.org/protocol/muc#stable_id"
 #define SELF_PING_FLAG   MUC_NS"#self-ping-optimization"
+#define MESSAGE_CORRECT_NS   "urn:xmpp:message-correct:0"
 
 /**
  * An XMPP component, communicating with an XMPP server using the protocole