Despite Serhiy's suggestion in issue18529, the emdash just looks
too long to me, at least in my browser.  This usage case is sort
of halfway between endash (connective) and emdash (pause/separator).

This arrangement means the sections that have summaries come
first, and everything else comes after those.

the same result as in 2.x.

the same result as in 2.x.

Also added a note about platform packagers not being required to install
pip by default, if they provide an appropriate pip hook, to the PEP
description section.

Also added refactoring and added basic tests for the argument
parsing in both ensurepip._main and ensurepip._uninstall._main.

This means I moved the 'new expected features' section to the top of the
summary, and made a new section with the same name at the start of
the body, turning the previous top level sections there into subsections.

I also added a line to the new first summary section for modulespec (pep 451).

The existing entry repeated the same info that was in the body text, which
means it didn't satisfy the sections "brevity" requirement :)