Merge bitcoin/bitcoin#23694: doc: Add missing optional to MempoolEntryDescription

fa1571b doc: Add missing optional to MempoolEntryDescription (MarcoFalke)

Pull request description:

  Needed for bitcoin/bitcoin#23083.

  Can be reviewed with `--word-diff-regex=.`.

ACKs for top commit:
  josibake:
    ACK bitcoin/bitcoin@fa1571b
  shaavan:
    ACK fa1571b

Tree-SHA512: b4370003d2aeadce438778e15bd9a0d6a7fef4711acbe8471a50a9d72bbf74e1705fecbaae6f7eb367ece7c795a816c4b8b6583ed6c8f91b35621ca30fd95c18

Author: MarcoFalke

src/rpc/blockchain.cpp

@@ -464,16 +464,23 @@ static RPCHelpMan getdifficulty()
 static std::vector<RPCResult> MempoolEntryDescription() { return {
     RPCResult{RPCResult::Type::NUM, "vsize", "virtual transaction size as defined in BIP 141. This is different from actual serialized size for witness transactions as witness data is discounted."},
     RPCResult{RPCResult::Type::NUM, "weight", "transaction weight as defined in BIP 141."},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "fee", "transaction fee, denominated in " + CURRENCY_UNIT + " (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "modifiedfee", "transaction fee with fee deltas used for mining priority, denominated in " + CURRENCY_UNIT + " (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "fee", /*optional=*/true,
+              "transaction fee, denominated in " + CURRENCY_UNIT + " (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "modifiedfee", /*optional=*/true,
+              "transaction fee with fee deltas used for mining priority, denominated in " + CURRENCY_UNIT +
+                  " (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
     RPCResult{RPCResult::Type::NUM_TIME, "time", "local time transaction entered pool in seconds since 1 Jan 1970 GMT"},
     RPCResult{RPCResult::Type::NUM, "height", "block height when transaction entered pool"},
     RPCResult{RPCResult::Type::NUM, "descendantcount", "number of in-mempool descendant transactions (including this one)"},
     RPCResult{RPCResult::Type::NUM, "descendantsize", "virtual transaction size of in-mempool descendants (including this one)"},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "descendantfees", "transaction fees of in-mempool descendants (including this one) with fee deltas used for mining priority, denominated in " + CURRENCY_ATOM + "s (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "descendantfees", /*optional=*/true,
+              "transaction fees of in-mempool descendants (including this one) with fee deltas used for mining priority, denominated in " +
+                  CURRENCY_ATOM + "s (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
     RPCResult{RPCResult::Type::NUM, "ancestorcount", "number of in-mempool ancestor transactions (including this one)"},
     RPCResult{RPCResult::Type::NUM, "ancestorsize", "virtual transaction size of in-mempool ancestors (including this one)"},
-    RPCResult{RPCResult::Type::STR_AMOUNT, "ancestorfees", "transaction fees of in-mempool ancestors (including this one) with fee deltas used for mining priority, denominated in " + CURRENCY_ATOM + "s (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
+    RPCResult{RPCResult::Type::STR_AMOUNT, "ancestorfees", /*optional=*/true,
+              "transaction fees of in-mempool ancestors (including this one) with fee deltas used for mining priority, denominated in " +
+                  CURRENCY_ATOM + "s (DEPRECATED, returned only if config option -deprecatedrpc=fees is passed)"},
     RPCResult{RPCResult::Type::STR_HEX, "wtxid", "hash of serialized transaction, including witness data"},
     RPCResult{RPCResult::Type::OBJ, "fees", "",
         {