Fix closing issue default pattern
Fix closing issue default pattern

* Complements gitlab-org/gitlab-ce!21531 relatively to
  gitlab-org/gitlab-ce#51085.

Signed-off-by: Samuele Kaplun <c4406f56465687f56a39fe72284a92a5db2f91ac@protonmail.com>

gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab,gitlabhq/omnibus-gitlab