🚸 Show possible subjects instead of "???"

src/store.js

@@ -71,7 +71,7 @@ export const parsedTimetable = computed(() => {
         );
         if (!matchingLesson) {
           matchingLesson = {
-            subject: "???",
+            subject: lesson.map((e) => e.subject).join(" / "),
             teacher: "Please configure a timetable group in the settings",
             length: lesson[0].length || 1,
           };