ax(node): rename n to connectionCount in ConnectedPeers usage example

AX Principle 1: predictable names over short names. The comment example
used `n` which requires context to understand; `connectionCount` is
self-documenting.

Co-Authored-By: Charon <charon@lethean.io>

pkg/node/transport.go

@@ -930,8 +930,8 @@ func (t *Transport) decryptMessage(data []byte, sharedSecret []byte) (*Message,
 	return &msg, nil
 }
 
-// n := transport.ConnectedPeers()
-// if n == 0 { return ErrNoPeers }
+// connectionCount := transport.ConnectedPeers()
+// if connectionCount == 0 { return ErrNoPeers }
 func (t *Transport) ConnectedPeers() int {
 	t.mutex.RLock()
 	defer t.mutex.RUnlock()