Merge #15669: rpc: Fix help text for signtransactionwithXXX

afc06fc rpc: Fix help text for signtransactionwithXXX (Torkel Rogstad)

Pull request description:

  This PR fixes the help text for the `signrawtransactionwithwallet` and `signrawtransactionwithkey` RPC calls. They both marked the `amount` field in the UTXO dependencies as required. This field is omitted in the [`rpc_rawtransaction.py` test](https://github.com/bitcoin/bitcoin/blob/8a8b03ecd2218dcdbcbf3127f2fa94f0f0da4698/test/functional/rpc_rawtransaction.py#L155) and [`successful_signing_test`](https://github.com/bitcoin/bitcoin/blob/8a8b03ecd2218dcdbcbf3127f2fa94f0f0da4698/test/functional/rpc_signrawtransaction.py#L42) in `rpc_signrawtransaction.py`.

ACKs for commit afc06f:
  promag:
    utACK afc06fc.
  MarcoFalke:
    utACK afc06fc

Tree-SHA512: 7847844ca38d8033fef2f5255700d21487d78a63ecee8b80362fa28fadfafc80ba29a89f38d7ebb3a1be4c7d47ff6c338f67afec9ee22bf065fb352bb3d03d3a

Author: MarcoFalke

src/rpc/rawtransaction.cpp

@@ -990,7 +990,7 @@ static UniValue signrawtransactionwithkey(const JSONRPCRequest& request)
                                     {"scriptPubKey", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "script key"},
                                     {"redeemScript", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "(required for P2SH) redeem script"},
                                     {"witnessScript", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "(required for P2WSH or P2SH-P2WSH) witness script"},
-                                    {"amount", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "The amount spent"},
+                                    {"amount", RPCArg::Type::AMOUNT, RPCArg::Optional::OMITTED, "(required for Segwit inputs) the amount spent"},
                                 },
                                 },
                         },

src/wallet/rpcwallet.cpp

@@ -3150,7 +3150,7 @@ UniValue signrawtransactionwithwallet(const JSONRPCRequest& request)
                                     {"scriptPubKey", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "script key"},
                                     {"redeemScript", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "(required for P2SH) redeem script"},
                                     {"witnessScript", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED, "(required for P2WSH or P2SH-P2WSH) witness script"},
-                                    {"amount", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "The amount spent"},
+                                    {"amount", RPCArg::Type::AMOUNT, RPCArg::Optional::OMITTED, "(required for Segwit inputs) the amount spent"},
                                 },
                             },
                         },