Fix typos; add typos package to CI

[elichad]

I spotted a couple of typos and ended up trying out the typos package to see if I could find more. It was pretty effective, so I added it to the CI.

The package primarily looks for typos of English words rather than checking all words against a fixed dictionary, so technical terms like "rocrate", "SHACL", etc are ignored. The only false positives I found were in one of the __init__.py files, so I skipped those.

[kikkomep]

Hi @elichad. Thanks for the typo fixes — the CI pipeline extension with the typos package is very useful.
After the latest merges into develop, there are some conflicts.
Once you’ve had a chance to resolve them, we can merge the PR.

[elichad]

Conflicts resolved :)

[kikkomep]

Great, thanks!