Primary motivation is documentation, but it will also hopefully simplify the code.
Also,
* Lower case the default output format names; this is in line with the custom ones (map keys) and how
it's treated all the places. This avoids doing `stringds.EqualFold` everywhere.
Closes#10896Closes#10620
We already have a lot of site building benchmarks. The main problem with adding the "Hugo site docs" to the list is that it cannot easiliy be compared to any previous release, because its content/template/whatever has changed.
This reverts commit 837e084bbe.
