Restore and document -ps / -nps option.

[des]

Summary

Sponsored by: Klara, Inc.

[des]

wording

[kevans]

LGTM, though I'd still give pstef a bit to weigh in as the de facto maintainer.

[pauamma_gundo.com]

Manual page English LGTM. Can't attest to anything else.

[pstef]

If it's just an effort to synchronize with OpenBSD then I vote against this change. I intentionally removed this option years ago, so I have to assume that the difference here comes from the fact that OpenBSD didn't.
If, however, you want to restore this functionality for whatever reason, I will only make a face and accept it.

Tangentially, if anybody wants to improve our indent, they should look into synchronizing with NetBSD indent. The story here is convoluted, so I'll spare you the details, but currently that one seems to be the most advanced fork of the BSD indents.

[des]

In D40788#928546, @pstef wrote:

If it's just an effort to synchronize with OpenBSD then I vote against this change. I intentionally removed this option years ago, so I have to assume that the difference here comes from the fact that OpenBSD didn't.
If, however, you want to restore this functionality for whatever reason, I will only make a face and accept it.

No, I'm not trying to synchronize with OpenBSD. I need this option for unrelated (or, rather, very indirectly related) reasons. I didn't realize we'd had it in the past; I'll amend the commit message to note that we're restoring it rather than copying it.