Librarian Bot: Add language metadata for dataset (#2)

- Librarian Bot: Add language metadata for dataset (ae3502e4624745aa9a782e62ae2a6dd56b1a3428)


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

README.md

@@ -1,4 +1,6 @@
 ---
+language:
+- ja
 dataset_info:
   features:
   - name: text