As of this commit, that layout doesn't exist yet, but I'm isolating the one-line
changes to their own commit to try and keep your eyes from glazing over.
This kinda-weird feature was previously quite severely under-documented in
terms of exactly what effect it has. This new documentation for it first
attempts to frame it as something that should be rarely used, and then
explains in more detail exactly how it behaves for different top-level
block types within the configuration.