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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{
    RPCHelpMan{
                "getrawtransaction",
                "\nReturn the raw transaction data.\n"
                "\nBy default this function only works for mempool transactions. When called with a blockhash\n"
                "argument, getrawtransaction will return the transaction if the specified block is available and\n"
                "the transaction is found in that block. When called without a blockhash argument, getrawtransaction\n"
                "will return the transaction if it is in the mempool, or if -txindex is enabled and the transaction\n"
                "is in a block in the blockchain.\n"
                "\nHint: Use gettransaction for wallet transactions.\n"
                "\nIf verbose is 'true', returns an Object with information about 'txid'.\n"
                "If verbose is 'false' or omitted, returns a string that is serialized, hex-encoded data for 'txid'.\n",
                {
                    {"txid", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The transaction id"},
                    {"verbose", RPCArg::Type::BOOL,  "false", "If false, return a string, otherwise return a json object"},
                    {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::OMITTED_NAMED_ARG, "The block in which to look for the transaction"},
                },