readme: add language tag

Hi,

as part of the #Hacktoberfest [2023](https://github.com/huggingface/hub-docs/issues/986) this MR extends the dataset metadata and adds a language tag.

Happy merging!

README.md

@@ -13,7 +13,9 @@ dataset_info:
     num_bytes: 139455.7357485349
     num_examples: 376
   download_size: 0
-  dataset_size: 1392332.0
+  dataset_size: 1392332
+language:
+- tr
 ---
 # Dataset Card for "turkishReviews-ds-mini"