multi: fixing it's/its typos in comments

routing/notifications.go

@@ -219,7 +219,7 @@ func createCloseSummaries(blockHeight uint32,
 
 // NetworkNodeUpdate is an update for a  node within the Lightning Network. A
 // NetworkNodeUpdate is sent out either when a new node joins the network, or a
-// node broadcasts a new update with a newer time stamp that supersedes it's
+// node broadcasts a new update with a newer time stamp that supersedes its
 // old update. All updates are properly authenticated.
 type NetworkNodeUpdate struct {
 	// Addresses is a slice of all the node's known addresses.

routing/router.go

@@ -1318,7 +1318,7 @@ func generateSphinxPacket(route *Route, paymentHash []byte) ([]byte,
 		return nil, nil, err
 	}
 
-	// Finally, encode Sphinx packet using it's wire representation to be
+	// Finally, encode Sphinx packet using its wire representation to be
 	// included within the HTLC add packet.
 	var onionBlob bytes.Buffer
 	if err := sphinxPacket.Encode(&onionBlob); err != nil {