Merge bitcoin/bitcoin#31413: rpc: Remove deprecated dummy alias for listtransactions::label

fa8e095 rpc: Remove deprecated dummy alias for listtransactions::label (MarcoFalke)

Pull request description:

  The RPC arg is not a dummy, but a label, so offering an undocumented alias is inconsistent with all other label interfaces and confusing at best, if not entirely unused.

  Fix it by removing the deprecated alias.

  This pull is a breaking change, but it should be limited, because it only affects someone using the deprecated named arg on this RPC. I can't imagine anyone doing this, because in all other places where label args are accepted, they are called `label`. If someone really didn't use `label` here as named arg, it would be trivial and less confusing for them to fix it up.

ACKs for top commit:
  achow101:
    ACK fa8e095
  rkrux:
    tACK fa8e095
  ryanofsky:
    Code review ACK fa8e095

Tree-SHA512: 0d0f3f53237ff9fac8c065b7d0a4245f5ff86efa427dbeeca711765494b7315a9d72b44751d346c76422847daf3d7ff90dbccb5ba200b089fb96128bd95da9f0

Author: achow101

src/wallet/rpc/transactions.cpp

@@ -1,4 +1,4 @@
-// Copyright (c) 2011-2022 The Bitcoin Core developers
+// Copyright (c) 2011-present The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -444,7 +444,7 @@ RPCHelpMan listtransactions()
                 "\nIf a label name is provided, this will return only incoming transactions paying to addresses with the specified label.\n"
                 "\nReturns up to 'count' most recent transactions skipping the first 'from' transactions.\n",
                 {
-                    {"label|dummy", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "If set, should be a valid label name to return only incoming transactions\n"
+                    {"label", RPCArg::Type::STR, RPCArg::Optional::OMITTED, "If set, should be a valid label name to return only incoming transactions\n"
                           "with the specified label, or \"*\" to disable filtering and return all transactions."},
                     {"count", RPCArg::Type::NUM, RPCArg::Default{10}, "The number of transactions to return"},
                     {"skip", RPCArg::Type::NUM, RPCArg::Default{0}, "The number of transactions to skip"},

test/functional/wallet_listtransactions.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# Copyright (c) 2014-2022 The Bitcoin Core developers
+# Copyright (c) 2014-present The Bitcoin Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """Test the listtransactions API."""
@@ -103,7 +103,6 @@ def run_test(self):
             txid = self.nodes[1].sendtoaddress(multisig["address"], 0.1)
             self.generate(self.nodes[1], 1)
             assert_equal(len(self.nodes[0].listtransactions(label="watchonly", include_watchonly=True)), 1)
-            assert_equal(len(self.nodes[0].listtransactions(dummy="watchonly", include_watchonly=True)), 1)
             assert len(self.nodes[0].listtransactions(label="watchonly", count=100, include_watchonly=False)) == 0
             assert_array_result(self.nodes[0].listtransactions(label="watchonly", count=100, include_watchonly=True),
                                 {"category": "receive", "amount": Decimal("0.1")},