RPCs that return detailed information about mempool entries (e.g. `getmempoolentry` and `getrawmempool(verbose=True)` include the fields `fee`, `modifiedfee`, `descendantfees`, and `ancestorfees` which were marked as "DEPRECATED" and replaced with a `fees` object field in #12240 (since v0.17).

We should remove these fields, but first, properly deprecate them using `-deprecatedrpc`.

#### Useful skills:

- basic understanding of Bitcoin Core RPC interface

#### Want to work on this issue?

For guidance on contributing, please read [CONTRIBUTING.md](https://github.com/bitcoin/bitcoin/blob/master/CONTRIBUTING.md) before opening your pull request.

{RPCResult::Type::OBJ, "transactionid", "", MempoolEntryDescription()},
                        }},
                    RPCResult{"for verbose = false and mempool_sequence = true",
                        RPCResult::Type::OBJ, "", "",
                        {
                            {RPCResult::Type::ARR, "txids", "",
                            {
                                {RPCResult::Type::STR_HEX, "", "The transaction id"},
                            }},
                            {RPCResult::Type::NUM, "mempool_sequence", "The mempool sequence value."},
                        }},
                },
                RPCExamples{
                    HelpExampleCli("getrawmempool", "true")
            + HelpExampleRpc("getrawmempool", "true")
                },
        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
{
    bool fVerbose = false;
    if (!request.params[0].isNull())
        fVerbose = request.params[0].get_bool();
    bool include_mempool_sequence = false;
    if (!request.params[1].isNull()) {
        include_mempool_sequence = request.params[1].get_bool();
    }
    return MempoolToJSON(EnsureAnyMemPool(request.context), fVerbose, include_mempool_sequence);
},
    };
}
static RPCHelpMan getmempoolancestors()