Update README to include link to documentation

Author: tekktrik

README.rst

@@ -101,15 +101,17 @@ Usage Example
     while ticks_less(ticks_ms(), deadline):
         pass
 
+Documentation
+=============
+
+API documentation for this library can be found on `Read the Docs <https://docs.circuitpython.org/projects/neopixel/en/latest/>`_.
+
+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>`_.
+
 Contributing
 ============
 
 Contributions are welcome! Please read our `Code of Conduct
 <https://github.com/adafruit/Adafruit_CircuitPython_ticks/blob/HEAD/CODE_OF_CONDUCT.md>`_
 before contributing to help this project stay welcoming.
-
-Documentation
-=============
-
-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>`_.