Update docs to reflect current behaviour

app/models/application_setting.rb

@@ -310,7 +310,7 @@ class ApplicationSetting < ActiveRecord::Base
 
     if ChronicDuration.parse(default_artifacts_expire_in).nil?
       errors.add(:default_artifacts_expire_in,
-        "can't be 0. Leave it blank for unlimited")
+        "can't be 0. Leave it blank for no expiration")
       false
     else
       true

app/views/admin/application_settings/_form.html.haml

@@ -220,7 +220,9 @@
         = f.text_field :default_artifacts_expire_in, class: 'form-control'
         .help-block
           Set the default expiration time for each job's artifacts
-          = link_to icon('question-circle'), help_page_path('user/admin_area/settings/continuous_integration', anchor: 'default-artifacts-expiration')
+          = surround '(', ')' do
+            = link_to 'syntax', help_page_path('ci/yaml/README', anchor: 'artifactsexpire_in')
+          = link_to icon('question-circle'), help_page_path('user/admin_area/settings/continuous_integration', anchor: 'default-artifacts-expiration-time')
 
   - if Gitlab.config.registry.enabled
     %fieldset

doc/user/admin_area/settings/continuous_integration.md

@@ -16,14 +16,14 @@ Note that this setting is set for each job.
 
 1. Hit **Save** for the changes to take effect.
 
-[art-yml]: ../../../administration/build_artifacts.md
+[art-yml]: ../../../administration/build_artifacts
 
 ## Default artifacts expiration time
 
 The default expiration time of the [build artifacts][art-yml] can be set in
-the Admin area of your GitLab instance. The value is in *days* and the
-default is 30 days. Note that this setting is set for each job. Set it to
-0 as never expired by default.
+the Admin area of your GitLab instance. The syntax of duration is described
+in [artifacts:expire_in][duration-syntax]. The default is `30 days`. Note that
+this setting is set for each job. Leave it blank for no default expiration.
 
 1. Go to **Admin area > Settings** (`/admin/application_settings`).
 
@@ -35,4 +35,5 @@ default is 30 days. Note that this setting is set for each job. Set it to
 
 1. Hit **Save** for the changes to take effect.
 
-[art-yml]: ../../../administration/build_artifacts.md
+[art-yml]: ../../../administration/build_artifacts
+[duration-syntax]: ../../../ci/yaml/README#artifactsexpire_in