rpc/createrawtransaction: redefine addresses as OBJ_USER_KEYS

The OBJ type is for actual objects with defined keys; OBJ_USER_KEYS is for objects with user-defined keys (such as the bitcoin address(es) in the createrawtransaction output object.

src/rpc/rawtransaction.cpp

@@ -397,7 +397,7 @@ static RPCHelpMan createrawtransaction()
                             "For compatibility reasons, a dictionary, which holds the key-value pairs directly, is also\n"
                             "                             accepted as second parameter.",
                         {
-                            {"", RPCArg::Type::OBJ, RPCArg::Optional::OMITTED, "",
+                            {"", RPCArg::Type::OBJ_USER_KEYS, RPCArg::Optional::OMITTED, "",
                                 {
                                     {"address", RPCArg::Type::AMOUNT, RPCArg::Optional::NO, "A key-value pair. The key (string) is the bitcoin address, the value (float or string) is the amount in " + CURRENCY_UNIT},
                                 },