feat(timetable): clear search bar when course is added to timetable (#3728)

* Clear search bar when a module is added to timetable

* Remove stale comment

Author: leslieyip02

website/src/views/timetable/ModulesSelect.tsx

@@ -77,8 +77,8 @@ const ModulesSelect: FC<Props> = ({
 
         case Downshift.stateChangeTypes.keyDownEnter:
         case Downshift.stateChangeTypes.clickItem:
-          // Don't reset isOpen, inputValue and highlightedIndex when item is selected
-          return omit(changes, ['isOpen', 'inputValue', 'highlightedIndex']);
+          setInputValue('');
+          return changes;
 
         case Downshift.stateChangeTypes.mouseUp:
           // TODO: Uncomment when we upgrade to Downshift v3