fixed doc comments

lib/screens/sharedWidgets/datum.dart

@@ -66,7 +66,7 @@ class _DatumState extends State<Datum> {
   }
 
   /// Shows date picker dialog and returns selected date
-  /// @return Future<DateTime?> Selected date or null if cancelled
+  /// @return Future[DateTime?] Selected date or null if cancelled
   Future<DateTime?> pickDate() async {
     final date = await showDatePicker(
         context: context,

lib/screens/sharedWidgets/var_text_field.dart

@@ -62,7 +62,7 @@ class _VarTextFieldState extends State<VarTextField> {
   }
 
   /// Load previous values from the appropriate database
-  /// @return Future<List<String>> List of previous values
+  /// @return Future[List[String]] List of previous values
   Future<List<String>> _loadData() async {
     List<Map<String, dynamic>> entries = [];
     List<Map<String, dynamic>> templatesEntries = [];