remove ConnectionID.Equal function

Connection IDs can now be compared with ==.

conn_id_generator.go

@@ -84,7 +84,7 @@ func (m *connIDGenerator) Retire(seq uint64, sentWithDestConnID protocol.Connect
 	if !ok {
 		return nil
 	}
-	if connID.Equal(sentWithDestConnID) {
+	if connID == sentWithDestConnID {
 		return &qerr.TransportError{
 			ErrorCode:    qerr.ProtocolViolation,
 			ErrorMessage: fmt.Sprintf("retired connection ID %d (%s), which was used as the Destination Connection ID on this packet", seq, connID),