Assorted fixes from trawling the sphinx logs - malformed formatting, broken references, leftovers from renaming action-task to action-callback and removing
yaml-templates, docstring fixes to make sphinx happier, and typos.
MozReview-Commit-ID: 6jUOljdLoE2
This is just enough to make these repos discoverable and suggest their usage.
Anything more would duplicate documentation in those repositories.
MozReview-Commit-ID: 1WNEsoQBB9U