Add diagnostics to ok tests

[codambro]

Support adding diagnostic lines under an ok test

To accept your contribution, please ensure that the checklist below is complete.

• Is your name/identity in the AUTHORS file?
• Does the code change (if the PR contains code) have 100% test coverage?
• Is CI passing all quality and testing checks?

[mblayman]

Hi @codambro, thanks for the contribution! I saw your PR and had to update tappy to prepare it for another release to include your change. Unfortunately, given the changes I made to file locations, that created conflicts here. Given that you change is fairly small, it may just be easier to start another PR and reapply your changes to the latest main. Whichever you decide, I'd be happy to accept your change once it's ready to merge.

[mblayman]

LGTM 👍 Thanks!

[mblayman]

Released as part of https://pypi.org/project/tap.py/3.2/