Update README.md (#8635)

examples/language-modeling/README.md

@@ -90,7 +90,7 @@ selected tokens (which may be part of words), they mask randomly selected words
 to that word). This technique has been refined for Chinese in [this paper](https://arxiv.org/abs/1906.08101).
 
 To fine-tune a model using whole word masking, use the following script:
-
+```bash
 python run_mlm_wwm.py \
     --model_name_or_path roberta-base \
     --dataset_name wikitext \