bug#37548: Implement sanitation of single-file package long description

[Stefan Kangas <stefan@marxist.se>]

Stefan Kangas <stefan@marxist.se> writes:

> Maybe it would make more sense to create a new function in package.el
> that takes care of this?  That way we don't have the same
> functionality in two places.

I noticed something else:  There is actually already code duplication
in package.el -- there is code to strip the commentary section in both
package--get-description and describe-package-1.

Perhaps it would make sense to look this all over and see how we can do better?

I also have two general questions, which are applicable to both your
recent patches:

1. It looks likely that this together with your other patch and your
previous contributions will together amount to more than 15 lines of
code.  That means that you would have to sign Copyright Assignment
papers for GNU Emacs.  I see you're emailing from gnu.org, so I assume
there are no surprises for you here; I guess Eli can help you sort
that out if it's not already.

2. Could you please provide a commit message formatted as a changelog
entry?  Details on this are in the CONTRIBUTE file in the repository.

Best regards,
Stefan Kangas