Update services templates docs

[ci skip]

doc/user/project/integrations/services_templates.md

-# Services Templates
+# Services templates
 
 A GitLab administrator can add a service template that sets a default for each
-project. This makes it much easier to configure individual projects.
+project. After a service template is enabled, it will be applied to new
+projects only and its details will be pre-filled on the project's Service page.
 
-After the template is created, the template details will be pre-filled on a
-project's Service page.
-
-## Enable a Service template
+## Enable a service template
 
 In GitLab's Admin area, navigate to **Service Templates** and choose the
 service template you wish to create.
 
-For example, in the image below you can see Redmine.
+## Services for external issue trackers
+
+In the image below you can see how a service template for Redmine would look
+like.
 
 ![Redmine service template](img/services_templates_redmine_example.png)
 
 ---
 
-**NOTE:** For each project, you will still need to configure the issue tracking
+For each project, you will still need to configure the issue tracking
 URLs by replacing `:issues_tracker_id` in the above screenshot with the ID used
 by your external issue tracker. Prior to GitLab v7.8, this ID was configured in
 the project settings, and GitLab would automatically update the URL configured
 in `gitlab.yml`. This behavior is now deprecated and all issue tracker URLs
-must be configured directly within the project's **Services** settings.
+must be configured directly within the project's **Integrations** settings.