Edited "Custom group-level project templates" for SSOT

doc/user/group/custom_project_templates.md

+---
+type: reference
+---
+
 # Custom group-level project templates **[PREMIUM]**
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab-ee/issues/6861) in [GitLab Premium](https://about.gitlab.com/pricing) 11.6.
@@ -24,3 +28,15 @@ Projects of nested subgroups of a selected template source cannot be used.
 
 Repository and database information that are copied over to each new project are
 identical to the data exported with [GitLab's Project Import/Export](../project/settings/import_export.md).
+
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