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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UniValue aMutable(UniValue::VARR);
    aMutable.push_back("time");
    aMutable.push_back("transactions");
    aMutable.push_back("prevblock");
    UniValue result(UniValue::VOBJ);
    result.pushKV("capabilities", aCaps);
    UniValue aRules(UniValue::VARR);
    UniValue vbavailable(UniValue::VOBJ);
    for (int j = 0; j < (int)Consensus::MAX_VERSION_BITS_DEPLOYMENTS; ++j) {
        Consensus::DeploymentPos pos = Consensus::DeploymentPos(j);
        ThresholdState state = VersionBitsState(pindexPrev, consensusParams, pos, versionbitscache);
        switch (state) {
            case ThresholdState::DEFINED:
            case ThresholdState::FAILED:
                
                break;
            case ThresholdState::LOCKED_IN:
                
                pblock->nVersion |= VersionBitsMask(consensusParams, pos);
                
            case ThresholdState::STARTED:
            {
                const struct VBDeploymentInfo& vbinfo = VersionBitsDeploymentInfo[pos];
                vbavailable.pushKV(gbt_vb_name(pos), consensusParams.vDeployments[pos].bit);
                if (setClientRules.find(vbinfo.name) == setClientRules.end()) {
                    if (!vbinfo.gbt_force) {
                        
                        pblock->nVersion &= ~VersionBitsMask(consensusParams, pos);
                    }
                }