Merge branch 'docs/ssot_admin_area_labels' into 'master'

Edit Admin Area *Labels* to comply with SSOT guidelines

See merge request gitlab-org/gitlab-ce!28528

doc/user/admin_area/labels.md

+---
+type: reference
+---
+
 # Labels administration **[CORE ONLY]**
 
-## Default Labels
+In the Admin Area, you can manage labels for the GitLab instance. For more details, see [Labels](../project/labels.md).
 
-### Define your own default Label Set
+## Default Labels
 
-Labels that are created within the Labels view on the Admin Dashboard will be automatically added to each new project.
+Labels created in the Admin Area become available to each _new_ project.
 
 ![Default label set](img/admin_labels.png)
+
+<!-- ## Troubleshooting
+
+Include any troubleshooting steps that you can foresee. If you know beforehand what issues
+one might have when setting this up, or when something is changed, or on upgrading, it's
+important to describe those, too. Think of things that may go wrong and include them here.
+This is important to minimize requests for support, and to avoid doc comments with
+questions that you know someone might ask.
+
+Each scenario can be a third-level heading, e.g. `### Getting error message X`.
+If you have none to add when creating a doc, leave this section in place
+but commented out to help encourage others to add to it in the future. -->