[Docs] Add language identifiers to fenced code blocks (#28955)

Add language identifiers to code blocks

docs/source/en/model_doc/lilt.md

@@ -39,7 +39,7 @@ The original code can be found [here](https://github.com/jpwang/lilt).
 - To combine the Language-Independent Layout Transformer with a new RoBERTa checkpoint from the [hub](https://huggingface.co/models?search=roberta), refer to [this guide](https://github.com/jpWang/LiLT#or-generate-your-own-checkpoint-optional).
 The script will result in `config.json` and `pytorch_model.bin` files being stored locally. After doing this, one can do the following (assuming you're logged in with your HuggingFace account):
 
-```
+```python
 from transformers import LiltModel
 
 model = LiltModel.from_pretrained("path_to_your_files")