Merge bitcoin/bitcoin#26991: doc: followups to #26471

47c174d doc: NetPermissionFlags for tx relay in blocksonly (willcl-ark)
e325e0f doc: Fix comment syntax error (willcl-ark)

Pull request description:

  Fix syntax error and specify `NetPermissionFlags` for whitelisted tx relay

ACKs for top commit:
  w0xlt:
    ACK bitcoin/bitcoin@47c174d

Tree-SHA512: eb579dc599a96a3ea79c01ac3e76160ec59cf71c2486c9401da8fbbd96ae756ba647aa9ba874835946bc76ba02782729da788617f982ae5a852139e10e7dfd75

Author: glozow

doc/reduce-memory.md

@@ -18,7 +18,7 @@ The size of some in-memory caches can be reduced. As caches trade off memory usa
 
 - Since `0.14.0`, unused memory allocated to the mempool (default: 300MB) is shared with the UTXO cache, so when trying to reduce memory usage you should limit the mempool, with the `-maxmempool` command line argument.
 
-- To disable most of the mempool functionality there is the `-blocksonly` option. This will reduce the default memory usage to 5MB and make the client opt out of receiving (and thus relaying) transactions, except from whitelisted peers and as part of blocks.
+- To disable most of the mempool functionality there is the `-blocksonly` option. This will reduce the default memory usage to 5MB and make the client opt out of receiving (and thus relaying) transactions, except from peers who have the `relay` permission set (e.g. whitelisted peers), and as part of blocks.
 
   - Do not use this when using the client to broadcast transactions as any transaction sent will stick out like a sore thumb, affecting privacy. When used with the wallet it should be combined with `-walletbroadcast=0` and `-spendzeroconfchange=0`. Another mechanism for broadcasting outgoing transactions (if any) should be used.
 

src/kernel/mempool_options.h

@@ -18,7 +18,7 @@ class CBlockPolicyEstimator;
 
 /** Default for -maxmempool, maximum megabytes of mempool memory usage */
 static constexpr unsigned int DEFAULT_MAX_MEMPOOL_SIZE_MB{300};
-//** Default for -maxmempool when blocksonly is set */
+/** Default for -maxmempool when blocksonly is set */
 static constexpr unsigned int DEFAULT_BLOCKSONLY_MAX_MEMPOOL_SIZE_MB{5};
 /** Default for -mempoolexpiry, expiration time for mempool transactions in hours */
 static constexpr unsigned int DEFAULT_MEMPOOL_EXPIRY_HOURS{336};