message: Update get difficulty for PoS
diff: @@ -442,6 +442,7 @@ UniValue getdifficulty(const JSONRPCRequest& request)
  throw runtime_error(
  "getdifficulty\n"
  "\nReturns the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
  + "\nReturns the proof-of-stake difficulty as a multiple of the minimum difficulty.\n"
  "\nResult:\n"
  "n.nnn (numeric) the proof-of-work difficulty as a multiple of the minimum difficulty.\n"
  "\nExamples:\n"
  @@ -450,7 +451,11 @@ UniValue getdifficulty(const JSONRPCRequest& request)
  );
  LOCK(cs_main);
  - return GetDifficulty();
  +
  + UniValue obj(UniValue::VOBJ);
  + obj.push_back(Pair("proof-of-work", GetDifficulty(GetLastBlockIndex(pindexBestHeader, false))));
  + obj.push_back(Pair("proof-of-stake", GetDifficulty(GetLastBlockIndex(pindexBestHeader, true))));
  + return obj;
  }
  std::string EntryDescriptionString()
  