Merge branch 'patch-6' into 'master'

add container registry images to not exported list

See the general Documentation guidelines http://docs.gitlab.com/ce/development/doc_styleguide.html

## What does this MR do?

Clarify that images are not exported

See merge request !7187

app/views/projects/edit.html.haml

@@ -181,6 +181,7 @@
           %ul
             %li Build traces and artifacts
             %li LFS objects
+            %li Container registry images
   %hr
   - if can? current_user, :archive_project, @project
     .row.prepend-top-default