Multiple line support for trailers and breaking change values

[pkryger]

According to git-interpret-trailers
Documentation trailer values
can be split over multiple lines. It seems that there was support for such a
behaviour added in #49. The functionality has been dropped when added support
for overflow in #64, but I cannot find a reason for it. The overflow support
has been subsequently removed in #68, unfortunately the multiple line trailer
values has not been reinstated. Can it be added again?

While on it, I believe that breaking change values should be also allowed to
span multiple line. Although, the BREAKING CHANGE doesn't conform to a
trailer key definition due to the whitespace(but BREAKING-CHANGE does!), I
believe that allowing multiple lines for a value will be beneficial: just the
key and a separator consume 17 characters, and an explanation may take more
than just a words (assuming: one cares about overflow).

I did a small test on my local
branch. Happy
to create a PR if that's something desireable.

[gbprod]

You're right !
I try to restore this soon

[gbprod]

Should be fixed now !

[pkryger]

Thank you very much for a speedy reaction! It works as expected now.