Update net_linux.go

net/net_linux.go

@@ -161,7 +161,7 @@ var netProtocols = []string{
 // If protocols is empty then all protocols are returned, otherwise
 // just the protocols in the list are returned.
 // Available protocols:
-//   ip,icmp,icmpmsg,tcp,udp,udplite
+// [ip,icmp,icmpmsg,tcp,udp,udplite]
 func ProtoCounters(protocols []string) ([]ProtoCountersStat, error) {
 	return ProtoCountersWithContext(context.Background(), protocols)
 }