Librarian Bot: Add language metadata for dataset (#1)

- Librarian Bot: Add language metadata for dataset (b6c20e37be438fe672cd1ecfa4453f77bf79ade9)


Co-authored-by: Librarian Bot (Bot) <librarian-bot@users.noreply.huggingface.co>

README.md

@@ -1,4 +1,6 @@
 ---
+language:
+- ja
 dataset_info:
 - config_name: default
   features: