fix(ci): autodoc was passing when it should not have been

[hutchic]

Summary

the autodoc CI test is passing when it should not be ( https://github.com/Kong/kong/runs/6726254426?check_suite_focus=true#step:7:15 ).

This PR makes it fail "correctly" aka if the autodoc fails CI will fail as intended

I'll leave the exercise to other to make the documentation fixes required to pass this PR.

[kikito]

I am pretty certain that this was my mistake. The autodocs script started its life as a manually-executed script, whose output would always be read by a human. I didn't think about the machines then. And later, when we added the ci check, I didn't remember that I had not thought about the machines.

Consider this a 👍 to the scripting change.

@flrgh Please add the upstreams.hash_on_query_arg docs so this passes.

just turn on errexit/set -e

I think we could add it. Our CI is already kind of flaky, though. Not feeling strongly either way. If you want to give it a try, I would suggest you give set -e a try, run the tests 2 or 3 times, and if you get any red, rollback to Colin's. Your call.

[flrgh]

Added the missing docs in #8903 and tested locally with success.