Update docs to mention naming conflicts with imported python modules

[greenaar]

Describe the bug
A clear and concise description of what the bug is. shows using lib/ for modules. This is fine UNLESS you are using the slack backend, which has a lib.py which occurs earlier in the search path.

The resulting error looks like an import failure, ModuleNotFoundError: No module named - when actually it's a naming collision.

To Reproduce
See #1687 for the discovery process

Expected behavior
The docs should choose a new name, OR highlight that the lib/ name could already be taken.

If desired, I'm happy to attempt an update to the docs with some verbiage around potential naming collisions.