add python example

README.md

@@ -2677,7 +2677,7 @@ This model only works for English texts. Long texts will be truncated to at most
 
 Below is an example for usage with sentence_transformers. `pip install sentence_transformers~=2.2.2`
 This is community contributed, and results may vary up to numerical precision.
-```
+```python
 from sentence_transformers import SentenceTransformer
 model = SentenceTransformer('intfloat/e5-small-v2')
 embeddings = model.encode(input_texts, normalize_embeddings=True)