In the 2nd edition of the Pro Git book, the Subtree Merging chapter has
been subsumed by an Advanced Merging chapter, which contains a
subsection on subtree merging.
Co-authored-by: hubwriter <hubwriter@github.com>
* Add back changes from prior to purge
* Manually fix some invalid Liquid
* Updoot render-content
* Improve test messages to show correct output
* Run el scripto
* Pass the remaining test