Merge bitcoin/bitcoin#27657: doc: Remove unused NO_BLOOM_VERSION constant

facbcd3 doc: Remove unused NO_BLOOM_VERSION constant (MarcoFalke)

Pull request description:

  This source code is the wrong place to document historic and now irrelevant details. Also, while touching the docs, clarify that the BIP 35 `mempool` message type is currently also guarded by the BIP 111 `NODE_BLOOM` flag, even though BIP 111 does not mention the `mempool` message type.

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Tree-SHA512: e69cf5cc2a4e6b061e8996bd9afc0c3e3c4e8174c086ecde425e0e9350b918f1c6612ce273ea1722d30e856049b83dada8782e7e96f676ae0112af85b22f868f

Author: fanquake

src/protocol.h

@@ -134,7 +134,8 @@ extern const char* GETADDR;
 /**
  * The mempool message requests the TXIDs of transactions that the receiving
  * node has verified as valid but which have not yet appeared in a block.
- * @since protocol version 60002.
+ * @since protocol version 60002 as described by BIP35.
+ *   Only available with service bit NODE_BLOOM, see also BIP111.
  */
 extern const char* MEMPOOL;
 /**
@@ -278,8 +279,6 @@ enum ServiceFlags : uint64_t {
     // set by all Bitcoin Core non pruned nodes, and is unset by SPV clients or other light clients.
     NODE_NETWORK = (1 << 0),
     // NODE_BLOOM means the node is capable and willing to handle bloom-filtered connections.
-    // Bitcoin Core nodes used to support this by default, without advertising this bit,
-    // but no longer do as of protocol version 70011 (= NO_BLOOM_VERSION)
     NODE_BLOOM = (1 << 2),
     // NODE_WITNESS indicates that a node can be asked for blocks and transactions including
     // witness data.

src/version.h

@@ -20,9 +20,6 @@ static const int MIN_PEER_PROTO_VERSION = 31800;
 //! BIP 0031, pong message, is enabled for all versions AFTER this one
 static const int BIP0031_VERSION = 60000;
 
-//! "filter*" commands are disabled without NODE_BLOOM after and including this version
-static const int NO_BLOOM_VERSION = 70011;
-
 //! "sendheaders" command and announcing blocks with headers starts with this version
 static const int SENDHEADERS_VERSION = 70012;