Consolidate Documentation sections of README

Author: tekktrik

README.rst

@@ -79,14 +79,11 @@ Documentation
 
 API documentation for this library can be found on `Read the Docs <https://docs.circuitpython.org/projects/ltr390/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_LTR390/blob/master/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>`_.