Merge branch 'fix-advanced-search-syntax-link' into 'master'

Fix the elasticsearch advanced search syntax link and edition details

See merge request !1958

app/views/search/_form.html.haml

@@ -15,5 +15,5 @@
     = button_tag "Search", class: "btn btn-success btn-search"
   - if current_application_settings.elasticsearch_search?
     .help-block
-      = link_to 'Advanced search functionality', help_page_path('user/search/advanced-search-syntax.md'), target: '_blank'
+      = link_to 'Advanced search functionality', help_page_path('user/search/advanced_search_syntax.md'), target: '_blank'
       is enabled.

doc/user/search/advanced_search_syntax.md

 # Advanced search syntax
 
 >**Notes:**
-- Introduced in [GitLab Enterprise Premium][ee] 9.2
+- Introduced in [GitLab Enterprise Starter][ee] 9.2
 - The [Elasticsearch integration](../../integration/elasticsearch.md) needs to
   be enabled