Also update example.

config/gitlab.yml.example

@@ -56,9 +56,10 @@ production: &base
     # signup_enabled: true
 
     ## Automatic issue closing
-    # If a commit message matches this regular express, all issues referenced from the matched text will be closed
-    # if it's pushed to a project's default branch.
-    # issue_closing_pattern: ^([Cc]loses|[Ff]ixes) +#\d+
+    # If a commit message matches this regular express, all issues referenced from the matched text will be closed.
+    # This  happends when the commit is pushed or merged into the default branch of a project.
+    # When not specified the default issue_closing_pattern as specified below will be used.
+    # issue_closing_pattern: ([Cc]loses|[Ff]ixes) +#\d+
 
     ## Default project features settings
     default_projects_features: