message: doc: Add missing "optional" to "long" estimaterawfee RPC help
  Also, use multi-line for arrays and objects
diff: @@ -908,7 +908,7 @@ static UniValue estimaterawfee(const JSONRPCRequest& request)
  " lower buckets."},
  },
  RPCResult{
  - "{\n"
  + "{ (json object) Results are returned for any horizon which tracks blocks up to the confirmation target\n"
  " \"short\" : { (json object, optional) estimate for short time horizon\n"
  " \"feerate\" : x.x, (numeric, optional) estimate fee rate in " + CURRENCY_UNIT + "/kB\n"
  " \"decay\" : x.x, (numeric) exponential decay (per block) for historical moving average of confirmation data\n"
  @@ -921,14 +921,22 @@ static UniValue estimaterawfee(const JSONRPCRequest& request)
  " \"inmempool\" : x.x, (numeric) current number of txs in mempool in the feerate range unconfirmed for at least target blocks\n"
  " \"leftmempool\" : x.x, (numeric) number of txs over history horizon in the feerate range that left mempool unconfirmed after target\n"
  " },\n"
  - " \"fail\" : { ... }, (json object, optional) information about the highest range of feerates to fail to meet the threshold\n"
  - " \"errors\": [ str... ] (json array of strings, optional) Errors encountered during processing\n"
  + " \"fail\" : { (json object, optional) information about the highest range of feerates to fail to meet the threshold\n"
  + " ...\n"
  + " },\n"
  + " \"errors\": [ (json array, optional) Errors encountered during processing\n"
  + " \"str\", (string)\n"
  + " ...\n"
  + " ],\n"
  + " },\n"
  + " \"medium\" : { (json object, optional) estimate for medium time horizon\n"
  + " ...\n"
  + " },\n"
  + " \"long\" : { (json object, optional) estimate for long time horizon\n"
  + " ...\n"
  " },\n"
  - " \"medium\" : { ... }, (json object, optional) estimate for medium time horizon\n"
  - " \"long\" : { ... } (json object) estimate for long time horizon\n"
  "}\n"
  "\n"
  - "Results are returned for any horizon which tracks blocks up to the confirmation target.\n"
  },
  RPCExamples{
  HelpExampleCli("estimaterawfee", "6 0.9")
  