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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{RPCResult::Type::NUM, "", "transactions before this one (by 1-based index in 'transactions' list) that must be present in the final block if this one is"},
                                            }},
                                        {RPCResult::Type::NUM, "fee", "difference in value between transaction inputs and outputs (in satoshis); for coinbase transactions, this is a negative Number of the total collected block fees (ie, not including the block subsidy); if key is not present, fee is unknown and clients MUST NOT assume there isn't one"},
                                        {RPCResult::Type::NUM, "sigops", "total SigOps cost, as counted for purposes of block limits; if key is not present, sigop cost is unknown and clients MUST NOT assume it is zero"},
                                        {RPCResult::Type::NUM, "weight", "total transaction weight, as counted for purposes of block limits"},
                                    }},
                            }},
                        {RPCResult::Type::OBJ, "coinbaseaux", "data that should be included in the coinbase's scriptSig content",
                        {
                            {RPCResult::Type::ELISION, "", ""},
                        }},
                        {RPCResult::Type::NUM, "coinbasevalue", "maximum allowable input to coinbase transaction, including the generation award and transaction fees (in satoshis)"},
                        {RPCResult::Type::OBJ, "coinbasetxn", "information for coinbase transaction",
                        {
                            {RPCResult::Type::ELISION, "", ""},
                        }},
                        {RPCResult::Type::STR, "target", "The hash target"},
                        {RPCResult::Type::NUM_TIME, "mintime", "The minimum timestamp appropriate for the next block time, expressed in " + UNIX_EPOCH_TIME},
                        {RPCResult::Type::ARR, "mutable", "list of ways the block template may be changed",
                            {
                                {RPCResult::Type::STR, "value", "A way the block template may be changed, e.g. 'time', 'transactions', 'prevblock'"},
                            }},
                        {RPCResult::Type::STR_HEX, "noncerange", "A range of valid nonces"},
                        {RPCResult::Type::NUM, "sigoplimit", "limit of sigops in blocks"},
                        {RPCResult::Type::NUM, "sizelimit", "limit of block size"},
                        {RPCResult::Type::NUM, "weightlimit", "limit of block weight"},
                        {RPCResult::Type::NUM_TIME, "curtime", "current timestamp in " + UNIX_EPOCH_TIME},
                        {RPCResult::Type::STR, "bits", "compressed target of next block"},
                        {RPCResult::Type::NUM, "height", "The height of the next block"},
                    }},