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:

Basic understanding of how to compile and run Bitcoin Core.

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},
                    {"replaceable", RPCArg::Type::BOOL,  "wallet default", "Allow this transaction to be replaced by a transaction with higher fees via BIP 125"},
                    {"conf_target", RPCArg::Type::NUM,  "wallet default", "Confirmation target (in blocks)"},
                    {"estimate_mode", RPCArg::Type::STR,  "UNSET", "The fee estimate mode, must be one of:\n"
            "       \"UNSET\"\n"
            "       \"ECONOMICAL\"\n"
            "       \"CONSERVATIVE\""},
                },
                 RPCResult{
                     RPCResult::Type::STR_HEX, "txid", "The transaction id for the send. Only 1 transaction is created regardless of\n"
            "the number of addresses."
                 },
                RPCExamples{
            "\nSend two amounts to two different addresses:\n"
            + HelpExampleCli("sendmany", "\"\" \"{\\\"" + EXAMPLE_ADDRESS[0] + "\\\":0.01,\\\"" + EXAMPLE_ADDRESS[1] + "\\\":0.02}\"") +
            "\nSend two amounts to two different addresses setting the confirmation and comment:\n"
            + HelpExampleCli("sendmany", "\"\" \"{\\\"" + EXAMPLE_ADDRESS[0] + "\\\":0.01,\\\"" + EXAMPLE_ADDRESS[1] + "\\\":0.02}\" 6 \"testing\"") +
            "\nSend two amounts to two different addresses, subtract fee from amount:\n"
            + HelpExampleCli("sendmany", "\"\" \"{\\\"" + EXAMPLE_ADDRESS[0] + "\\\":0.01,\\\"" + EXAMPLE_ADDRESS[1] + "\\\":0.02}\" 1 \"\" \"[\\\"" + EXAMPLE_ADDRESS[0] + "\\\",\\\"" + EXAMPLE_ADDRESS[1] + "\\\"]\"") +
            "\nAs a JSON-RPC call\n"
            + HelpExampleRpc("sendmany", "\"\", {\"" + EXAMPLE_ADDRESS[0] + "\":0.01,\"" + EXAMPLE_ADDRESS[1] + "\":0.02}, 6, \"testing\"")
                },
    }.Check(request);
    
    
    pwallet->BlockUntilSyncedToCurrentChain();
    auto locked_chain = pwallet->chain().lock();
    LOCK(pwallet->cs_wallet);
    if (!request.params[0].isNull() && !request.params[0].get_str().empty()) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Dummy value must be set to \"\"");