Merge bitcoin/bitcoin#23139: rpc: fix "trusted" field in TransactionDescriptionString(), add coverage

66f6efc70a rpc: improve TransactionDescriptionString() "generated" help (Jon Atack)
296cfa312f test: add listtransactions/listsinceblock "trusted" coverage (Jon Atack)
d95913fc43 rpc: fix "trusted" description in TransactionDescriptionString (Jon Atack)

Pull request description:

  The RPC gettransaction, listtransactions, and listsinceblock helps returned by `TransactionDescriptionString()` inform the user that the `trusted` boolean field is only present if the transaction is trusted and safe to spend from.

  The field is in fact returned by `WalletTxToJSON()` when the transaction has 0 confirmations (or negative confirmations, if conflicted), and it can be true or false.

  This patch fixes the help, adds test coverage, and touches up the help for the neighboring `generate` field.

ACKs for top commit:
  rajarshimaitra:
    tACK https://github.com/bitcoin/bitcoin/pull/23139/commits/66f6efc70a72cc1613906fd3c10281f9af0ba0db
  theStack:
    Tested ACK 66f6efc70a

Tree-SHA512: 4c2127765b82780e07bbdbf519d27163d414d9f15598e01e02210f210e6009be344c84951d7274e747b1386991d4c3b082cd25aebe885fb8cf0b92d57178f68e

test/functional/wallet_listtransactions.py

@@ -31,10 +31,10 @@ class ListTransactionsTest(BitcoinTestFramework):
         self.sync_all()
         assert_array_result(self.nodes[0].listtransactions(),
                             {"txid": txid},
-                            {"category": "send", "amount": Decimal("-0.1"), "confirmations": 0})
+                            {"category": "send", "amount": Decimal("-0.1"), "confirmations": 0, "trusted": True})
         assert_array_result(self.nodes[1].listtransactions(),
                             {"txid": txid},
-                            {"category": "receive", "amount": Decimal("0.1"), "confirmations": 0})
+                            {"category": "receive", "amount": Decimal("0.1"), "confirmations": 0, "trusted": False})
         self.log.info("Test confirmations change after mining a block")
         blockhash = self.generate(self.nodes[0], 1)[0]
         blockheight = self.nodes[0].getblockheader(blockhash)['height']