Fix note about model serialization BC guarantee (#4363)

Author: NicolasHug

docs/source/models.rst

@@ -9,10 +9,10 @@ keypoint detection and video classification.
 
 .. note ::
     Backward compatibility is guaranteed for loading a serialized 
-    `state_dict` to the model created using old PyTorch version. 
+    ``state_dict`` to the model created using old PyTorch version. 
     On the contrary, loading entire saved models or serialized 
-    `ScriptModules` (seralized using older versions of PyTorch) 
-    will preserve the historic behaviour. Refer to the following 
+    ``ScriptModules`` (seralized using older versions of PyTorch) 
+    may not preserve the historic behaviour. Refer to the following 
     `documentation 
     <https://pytorch.org/docs/stable/notes/serialization.html#id6>`_