message: doc: comment out and add annotation to unused MSG_FILTERED_WITNESS_BLOCK
diff: @@ -398,7 +398,9 @@ enum GetDataMsg : uint32_t {
  MSG_CMPCT_BLOCK = 4, //!< Defined in BIP152
  MSG_WITNESS_BLOCK = MSG_BLOCK | MSG_WITNESS_FLAG, //!< Defined in BIP144
  MSG_WITNESS_TX = MSG_TX | MSG_WITNESS_FLAG, //!< Defined in BIP144
  - MSG_FILTERED_WITNESS_BLOCK = MSG_FILTERED_BLOCK | MSG_WITNESS_FLAG,
  + // MSG_FILTERED_WITNESS_BLOCK is defined in BIP144 as reserved for future
  + // use and remains unused.
  + // MSG_FILTERED_WITNESS_BLOCK = MSG_FILTERED_BLOCK | MSG_WITNESS_FLAG,
  };
  /** inv message data */
  