update TODO

Author: nerdoc

TODO.md

@@ -1,7 +1,8 @@
 ## TODO
 
-Translating of following files:
-
-* Parser, ParserTest
-* Message, MessageTest 
-* Python 3.10: replace Union[x,y] with | in annotations
+* Translation of following files:
+  * Parser, ParserTest
+  * Message, MessageTest 
+* When Python 3.10 is adapted: 
+  * replace Union[x,y] with x|y and Optional[x] with x|None in annotations
+  * use f-strings instead of .format-strings