add fourwire to mock docs list

Author: FoamyGuy

docs/conf.py

@@ -25,7 +25,7 @@
 # Uncomment the below if you use native CircuitPython modules such as
 # digitalio, micropython and busio. List the modules you use. Without it, the
 # autodoc module docs will fail to generate with a warning.
-autodoc_mock_imports = ["epaperdisplay"]
+autodoc_mock_imports = ["epaperdisplay", "fourwire"]
 
 autodoc_preserve_defaults = True