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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"                         Specify a fee rate instead of relying on the built-in fee estimator.\n"
            "                         Must be at least 0.0001 BTC per kB higher than the current transaction fee rate.\n"},
                            {"replaceable", RPCArg::Type::BOOL,  "true", "Whether the new transaction should still be\n"
            "                         marked bip-125 replaceable. If true, the sequence numbers in the transaction will\n"
            "                         be left unchanged from the original. If false, any input sequence numbers in the\n"
            "                         original transaction that were less than 0xfffffffe will be increased to 0xfffffffe\n"
            "                         so the new transaction will not be explicitly bip-125 replaceable (though it may\n"
            "                         still be replaceable in practice, for example if it has unconfirmed ancestors which\n"
            "                         are replaceable)."},
                            {"estimate_mode", RPCArg::Type::STR,  "UNSET", "The fee estimate mode, must be one of:\n"
            "         \"UNSET\"\n"
            "         \"ECONOMICAL\"\n"
            "         \"CONSERVATIVE\""},
                        },
                        "options"},
                },
                RPCResult{
                    RPCResult::Type::OBJ, "", "", {
                        {RPCResult::Type::STR, "psbt", "The base64-encoded unsigned PSBT of the new transaction. Only returned when wallet private keys are disabled."},
                        {RPCResult::Type::STR_HEX, "txid", "The id of the new transaction. Only returned when wallet private keys are enabled."},
                        {RPCResult::Type::STR_AMOUNT, "origfee", "The fee of the replaced transaction."},
                        {RPCResult::Type::STR_AMOUNT, "fee", "The fee of the new transaction."},
                        {RPCResult::Type::ARR, "errors", "Errors encountered during processing (may be empty).",
                        {
                            {RPCResult::Type::STR, "", ""},
                        }},
                    }
                },
                RPCExamples{
            "\nBump the fee, get the new transaction\'s txid\n" +