bolt1: include the port for signet network

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

01-messaging.md

@@ -8,9 +8,10 @@ This protocol assumes an underlying authenticated and ordered transport mechanis
 The default TCP port depending from the network used. The most common networks are:
 
 - Bitcoin mainet with port number 9735 or the corresponding hexadecimal `0x2607`;
-- Bitcoin testnet with port number 19735 (`0x4D17`).
+- Bitcoin testnet with port number 19735 (`0x4D17`);
+- Bitcoin signet with port number 39735 (`0xF87`).
 
-The Unicode code point for LIGHTNING <sup>[1](#reference-1)</sup>, and the port convention try to follow the Bitcoin 0.22 convention.
+The Unicode code point for LIGHTNING <sup>[1](#reference-1)</sup>, and the port convention try to follow the Bitcoin Core convention.
 
 All data fields are unsigned big-endian unless otherwise specified.