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.

{
    
    const std::string EXAMPLE_DESCRIPTOR_RAW = "raw(76a91411b366edfc0a8b66feebae5c2e25a7b6a5d1cf3188ac)#fm24fxxy";
    return RPCHelpMan{"scantxoutset",
        "\nScans the unspent transaction output set for entries that match certain output descriptors.\n"
        "Examples of output descriptors are:\n"
        "    addr(<address>)                      Outputs whose scriptPubKey corresponds to the specified address (does not include P2PK)\n"
        "    raw(<hex script>)                    Outputs whose scriptPubKey equals the specified hex scripts\n"
        "    combo(<pubkey>)                      P2PK, P2PKH, P2WPKH, and P2SH-P2WPKH outputs for the given pubkey\n"
        "    pkh(<pubkey>)                        P2PKH outputs for the given pubkey\n"
        "    sh(multi(<n>,<pubkey>,<pubkey>,...)) P2SH-multisig outputs for the given threshold and pubkeys\n"
        "\nIn the above, <pubkey> either refers to a fixed public key in hexadecimal notation, or to an xpub/xprv optionally followed by one\n"
        "or more path elements separated by \"/\", and optionally ending in \"/*\" (unhardened), or \"/*'\" or \"/*h\" (hardened) to specify all\n"
        "unhardened or hardened child keys.\n"
        "In the latter case, a range needs to be specified by below if different from 1000.\n"
        "For more information on output descriptors, see the documentation in the doc/descriptors.md file.\n",
        {
            {"action", RPCArg::Type::STR, RPCArg::Optional::NO, "The action to execute\n"
                "\"start\" for starting a scan\n"
                "\"abort\" for aborting the current scan (returns true when abort was successful)\n"
                "\"status\" for progress report (in %) of the current scan"},
            {"scanobjects", RPCArg::Type::ARR, RPCArg::Optional::OMITTED, "Array of scan objects. Required for \"start\" action\n"
                "Every scan object is either a string descriptor or an object:",
            {