updated conf.py; bus device intersphinx link

Author: sommersoft

docs/conf.py

@@ -20,7 +20,7 @@
 # autodoc module docs will fail to generate with a warning.
 autodoc_mock_imports = ["adafruit_bus_device", "micropython"]
 
-intersphinx_mapping = {'python': ('https://docs.python.org/3.4', None),
+intersphinx_mapping = {'python': ('https://docs.python.org/3.4', None),'BusDevice': ('https://circuitpython.readthedocs.io/projects/busdevice/en/latest/', None),
                        'CircuitPython': ('https://circuitpython.readthedocs.io/en/latest/', None)}
 
 # Add any paths that contain templates here, relative to this directory.