Merge branch 'cc/trailers-corner-case-fix'

"interpret-trailers" helper mistook a single-liner log message that
has a colon as the end of existing trailer.

* cc/trailers-corner-case-fix:
  trailer: retitle a test and correct an in-comment message
  trailer: ignore first line of message

diff --cc t/t7513-interpret-trailers.sh
Simple merge

diff --cc trailer.c
Simple merge