Fix some type hints

Fixes #162

app/models.py

@@ -486,9 +486,9 @@ class PlaylistRows(Base):
 
     @classmethod
     def get_unplayed_rows(cls, session: Session,
-                          playlist_id: int) -> List[int]:
+                          playlist_id: int) -> List["PlaylistRows]:
         """
-        For passed playlist, return a list of track rows that
+        For passed playlist, return a list of playlist rows that
         have not been played.
         """
 

app/musicmuster.py

@@ -932,7 +932,7 @@ class Window(QMainWindow, Ui_MainWindow):
             unplayed_plrs = PlaylistRows.get_unplayed_rows(
                 session, playlist_id)
             if helpers.ask_yes_no("Move tracks",
-                                  f"Move {len(unplayed_playlist_rows)} tracks:"
+                                  f"Move {len(unplayed_plrs)} tracks:"
                                   " Are you sure?"
                                   ):
                 self.move_playlist_rows(session, unplayed_plrs)