Best practice for inlined doctests

[cmungall]

Currently we don't run doctest as part of github actions. One reason not to do this is that many of the inline documentation examples make use of a variety real-world ontologies rather than the toy examples checked into tests/input. Running these with github actions would not be ideal, as every action run would end up syncing multiple sqlite databases.

I am not sure what the best strategy is here. I like having real-world ontology examples (though this also introduces a test fragility problem, where if the ontology changes the test result changes). But I also like a PR test to be comprehensive

Related:

• Add more code to docstrings #525