fix grammar

Author: WilliamYue37

src/opentau/datasets/vqa/base.py

@@ -150,5 +150,5 @@ def _separate_image_in_time(self, item: dict) -> None:
         Args:
             item: Item dictionary (unmodified).
         """
-        # VQA datasets has nothing to separate.
+        # VQA datasets have nothing to separate.
         pass