Rename Note to Grade

cmd/lsf/main.go

@@ -46,12 +46,11 @@ func main() {
 func cmdGrades(cmd *cli.Cmd) {
 	cmd.Before = sessionNeeded
 	cmd.Action = func() {
-		noten, err := s.Noten()
+		grades, err := s.Grades()
 		if err != nil {
 			log.Fatal(err)
 		}
-		fmt.Println("Noten:")
-		noten.Print()
+		grades.Print()
 	}
 }