Minor annoyance with 'git interpret-trailers'

Hi,

I use 'git interpret-trailers' as a commit-msg hook to add a Signed-off-by in a repository.

When used in a one-line commit message formatted like 'foo: do something', the command interprets the one-line summary as a trailer, and inserts my Signed-off-by after it, without a blank line:

    foo: do something
    Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>

This breaks the convention "One summary line, one blank line, and then body", and shows my sign-off in the output of "git log --oneline" :-(.

I think the behavior "don't insert a newline if the last line looks like a trailer" should be disabled when the message is a one-liner.

Cheers,