Having multiple paragraphs in a few news entry lead to inconsistent
spacing while rendered in HTML by mixing "visually compact lists"
(when no entry of the whole list contains multiple paragraphs) and
"sparse lists" (when at least one do).
bpo-26510 in 3.7.0a2 changed the behavior of argparse to make
subparsers required by default, returning to the behavior of 2.7
and 3.2. The behavior was changed in 3.3 to be no longer required.
While it might make more sense to have the default to required,
compatibility with 3.3 through 3.6 is probably less disruptive
than trying to reintroduce compatibility with 2.7 at this point.
This change restores the 3.6 behavior.
Hugo van Kemenade
Julien Palard
Stéphane Wirtel
Serhiy Storchaka
Ned Deily
luzpaz
Barry Warsaw