Improve language tag

Hi! As the model is multilingual, this is a PR to add other languages than English to the language tag to improve the referencing. Note that 29 languages are announced in the README, but only 13 are explicitly listed. I was therefore only able to add these 13 languages.

README.md

@@ -1,11 +1,23 @@
----
-license: apache-2.0
-datasets:
-- SJTULean/LeanStatement_CoT
-language:
-- en
-base_model:
-- Qwen/Qwen2.5-7B-Instruct
----
-
+---
+license: apache-2.0
+datasets:
+- SJTULean/LeanStatement_CoT
+language:
+- zho
+- eng
+- fra
+- spa
+- por
+- deu
+- ita
+- rus
+- jpn
+- kor
+- vie
+- tha
+- ara
+base_model:
+- Qwen/Qwen2.5-7B-Instruct
+---
+
 Wishing users to be clear that the model's formalization ability is (contrastivelty) relatively faible compared to LeanStatement_SFT and PPO, thus may only be considered as an experimental model.