The extra whitespace was targeted at machine processing for a subset of
users for a subset of runs of CLIs. On the other hand, there is a lot
of concern over the extra verbose output.
A user can set the help template for man, if desired. They can even do
something (env? feature flag?) to make it only run when doing man
generation. We also have #3174 in the works.
So let's focus on the end-user reading `--help`. People wanting to use
`help2man` have workarounds to do what they need.
Fixes#3096
The main care about is that when we override a `flatten` / `subcommand`
doc comment in a parent container, that we make sure we take nothing
from the child container, rather than implicitly taking one `about` ut
not `long_about`.
To do this, and to play the most safe with long help detection, we reset
`long_about` to default when there is no doc comment body to use for
`long_about`.
Fixes#2983
