The obvious way to fix this would be to adapt lines to split on null.

However, it's actually nontrivial to rewrite lines. In particular it has a
weird implementation to avoid a space leak. See:
https://gitlab.haskell.org/ghc/ghc/-/issues/4334

Also, while that is a small amount of code, it's covered by a rather
complex copyright and I'd have to include that copyright in git-annex.

So, I opted to filter out the trailing empty string instead.

Sponsored-by: Dartmouth College's Datalad project