Add comment about README.rst rendered on GH

Author: benjaoming

README.rst

@@ -1,6 +1,8 @@
 Example: Basic Sphinx project for Read the Docs
 ===============================================
 
+.. This README.rst should work on Github and is also included in the Sphinx documentation project in docs/ - therefore, README.rst uses absolute links for most things so it renders properly on GitHub
+
 This example shows the an integration of a basic Sphinx project with Read the Docs. You're encouraged to view it to get inspiration and copy & paste from the files in the source code. If you are using Read the Docs for the first time, have a look at the official `Read the Docs Tutorial <https://docs.readthedocs.io/en/stable/tutorial/index.html>`_.
 
 📚 `docs/ <https://github.com/readthedocs-examples/example-sphinx-basic/blob/main/docs/>`_