* Remove nitty-gritty details about custom-style filters (it won't make
sense to readers unfamiliar with filters, and would be obvious to
users already familiar with them).
* Fix a capitalization.
Make it clearer that structured author variables require a custom
template.
Many thanks to John Muccigrosso (@Jmuccigr) for his help in addressing
this issue.
This supersedes and closes#2148.