Add "Moving tiers" item to docs MR template

.gitlab/merge_request_templates/Documentation.md

@@ -19,6 +19,7 @@ Closes
 - [ ] [Apply the correct labels and milestone](https://docs.gitlab.com/ee/development/documentation/workflow.html#2-developer-s-role-in-the-documentation-process)
 - [ ] Crosslink the document from the higher-level index
 - [ ] Crosslink the document from other subject-related docs
+- [ ] Feature moving tiers? Make sure the change is also reflected in [`features.yml`](https://gitlab.com/gitlab-com/www-gitlab-com/blob/master/data/features.yml)
 - [ ] Correctly apply the product [badges](https://docs.gitlab.com/ee/development/documentation/styleguide.html#product-badges) and [tiers](https://docs.gitlab.com/ee/development/documentation/styleguide.html#gitlab-versions-and-tiers)
 - [ ] [Port the MR to EE (or backport from CE)](https://docs.gitlab.com/ee/development/documentation/index.html#cherry-picking-from-ce-to-ee): _always recommended, required when the `ee-compat-check` job fails_