The new empty line is inserted before the editor is opened.

This is from HEAD, can be observed by running "darcs record" without -m
flag or with "darcs amend --edit".

I stumbled over this more than once. You have to remember to delete the
empty line (before the comments). I agree that we should fix this.

One possibility would be to delete trailing newlines from the long
comment before we store it. This would make the long comments robust
against this particular formatting error.