5.0/5.1 coredev Products.Archetypes tests fail without this PR

Folks, I would like to see this merged today -- fixes a regression in reStructuredText header levels introduced in 2.2.0 vs. the original Zope2 reStructuredText wrapper:


Without this fix, multiple Products.Archetypes BaseUnit tests fail in both 5.0.x and 5.1.x buildout.coredev.

This pull request is 20 days old, and checks pass -- if there are no takers to review, I will merge it myself tomorrow.


I had glanced at this pull request a few times the past days or weeks. I was a bit hesitant, because I was thinking: why aren't the coredev tests on Jenkins failing?
I have created a coredev pull request to check that, but your fix seems good, so I have merged it.
See the pull request for more info.