Update README.md

Author: vincentamato

esm/README.md

@@ -56,7 +56,7 @@ logits = result["logits"]  # Shape: (batch, length, vocab_size)
 
 ### Masked Language Modeling
 
-```python
+```bash
 # For a complete example, see main.py
 python main.py --sequence "YOUR_SEQUENCE" --mask-position 50
 ```