Add hugs (#5225)

docs/source/model_summary.rst

@@ -1,7 +1,7 @@
 Summary of the models
 ================================================
 
-This is a summary of the models available in the transformers library. It assumes you’re familiar with the original 
+This is a summary of the models available in 🤗 Transformers. It assumes you’re familiar with the original 
 `transformer model <https://arxiv.org/abs/1706.03762>`_. For a gentle introduction check the `annotated transformer 
 <http://nlp.seas.harvard.edu/2018/04/03/attention.html>`_. Here we focus on the high-level differences between the
 models. You can check them more in detail in their respective documentation. Also checkout the