The RPC docs are now enforced to specify the json type of the args and results at compile time. However, some help texts contain the type twice. (E.g. https://github.com/bitcoin/bitcoin/pull/17809#discussion_r386295217 ). The duplicate type in the description should be removed.

Duplicates can be found with this command:

```sh
git grep --extended-regexp  'RPC.*(ARR|OBJ).*json (array|object)' src/rpc/ src/wallet/rpc*
```

#### Useful skills:

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if ((int)ret.size() >= (nCount+nFrom)) break;
        }
    }
    
    if (nFrom > (int)ret.size())
        nFrom = ret.size();
    if ((nFrom + nCount) > (int)ret.size())
        nCount = ret.size() - nFrom;
    const std::vector<UniValue>& txs = ret.getValues();
    UniValue result{UniValue::VARR};
    result.push_backV({ txs.rend() - nFrom - nCount, txs.rend() - nFrom }); 
    return result;
}
static UniValue listsinceblock(const JSONRPCRequest& request)
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    const CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
            RPCHelpMan{"listsinceblock",
                "\nGet all transactions in blocks since block [blockhash], or all transactions if omitted.\n"
                "If \"blockhash\" is no longer a part of the main chain, transactions from the fork point onward are included.\n"
                "Additionally, if include_removed is set, transactions affecting the wallet which were removed are returned in the \"removed\" array.\n",
                {
                    {"blockhash", RPCArg::Type::STR, RPCArg::Optional::OMITTED_NAMED_ARG, "If set, the block hash to list transactions since, otherwise list all transactions."},
                    {"target_confirmations", RPCArg::Type::NUM,  "1", "Return the nth block hash from the main chain. e.g. 1 would mean the best block hash. Note: this is not used as a filter, but only affects [lastblock] in the return value"},
                    {"include_watchonly", RPCArg::Type::BOOL,  "true for watch-only wallets, otherwise false", "Include transactions to watch-only addresses (see 'importaddress')"},
                    {"include_removed", RPCArg::Type::BOOL,  "true", "Show transactions that were removed due to a reorg in the \"removed\" array\n"
            "                                                           (not guaranteed to work on pruned nodes)"},