Removed building locally section from README, replaced with documentation section

Author: evaherrada

README.rst

@@ -65,25 +65,7 @@ Contributions are welcome! Please read our `Code of Conduct
 <https://github.com/adafruit/Adafruit_CircuitPython_Requests/blob/master/CODE_OF_CONDUCT.md>`_
 before contributing to help this project stay welcoming.
 
-Sphinx documentation
------------------------
-
-Sphinx is used to build the documentation based on rST files and comments in the code. First,
-install dependencies (feel free to reuse the virtual environment from above):
-
-.. code-block:: shell
-
-    python3 -m venv .env
-    source .env/bin/activate
-    pip install Sphinx sphinx-rtd-theme
-
-Now, once you have the virtual environment activated:
-
-.. code-block:: shell
-
-    cd docs
-    sphinx-build -E -W -b html . _build/html
+Documentation
+=============
 
-This will output the documentation to ``docs/_build/html``. Open the index.html in your browser to
-view them. It will also (due to -W) error out on any warning like Travis will. This is a good way to
-locally verify it will pass.
+For information on building library documentation, please check out `this guide <https://learn.adafruit.com/creating-and-sharing-a-circuitpython-library/sharing-our-docs-on-readthedocs#sphinx-5-1>`_.