Update Documentation link in the readme (#440)

Author: VaultVulp

README.rst

@@ -204,7 +204,7 @@ Here's a basic example (for more see the *examples* section of the docs):
 Documentation
 =============
 
-Documentation is available at [pymongo.readthedocs.io](https://pymongo.readthedocs.io/en/stable/).
+Documentation is available at `pymongo.readthedocs.io <https://pymongo.readthedocs.io/en/stable/>`_.
 
 To build the documentation, you will need to install sphinx_.
 Documentation can be generated by running **python