Fixes #3525 (I think).
Partially addresses #1771.
Related to #1730 and #574.

Fixes #3525 (I think).

Well, technically this PR doesn't fix #3525, but the merge to master will :)

I'm creating an extension for tools/check.sh to detect hanging paragraphs using sed and awk.

Ah, we were both working on this at the same time. I built a perl script to do this; do you prefer one approach or the other?

My check script is here: #4170

Fixes #3525 (I think).

Well, technically this PR doesn't fix #3525, but the merge to master will :)

Maybe not:

# FIXME: We should also check for subclauses that have no siblings.

Does your script fix this, @jensmaurer?

@zygoloid , your script introduces a dependency on perl, which is novel for the check.sh script. My variant just uses sed and awk.

@JohelEGP , no, my script does not check for lone siblings. I think those only currently appear together with hanging paragraphs.

I've marked as done those that will be fixed by this. Please, do check the others: #3525.

@zygoloid , your script introduces a dependency on perl, which is novel for the check.sh script. My variant just uses sed and awk.

For what it's worth, using perl here is actually more portable than your uses of awk (which rely on GNU awk-isms, and consequently don't work out of the box on Mac OS). But I'm fine sticking with something more similar to what we already do here if there's a worry that perl won't be available. Dropping the checking part from this PR.

@zygoloid , I think I'm not using GNU awk specifics, at least not in the "hanging paragraph" check.
(I think you discovered a GNU sed dependency, though.)

Sorry, you're right, it's sed not awk that's the problem in this script in general.

See also follow-up fixes #4173 and #4174.