multi: fix typos in comments

channeldb/channel_test.go

@@ -488,7 +488,7 @@ func TestChannelStateTransition(t *testing.T) {
 		t.Fatalf("unable to add to commit chain: %v", err)
 	}
 
-	// The commitment tip should now match the the commitment that we just
+	// The commitment tip should now match the commitment that we just
 	// inserted.
 	diskCommitDiff, err := channel.RemoteCommitChainTip()
 	if err != nil {