Add tooltip info about issue move filed purpose

app/views/shared/issuable/_form.html.haml

@@ -84,6 +84,10 @@
       - projects = project_options(issuable, current_user, ability: :admin_issue)
       = select_tag(:move_to_project_id, projects, include_blank: true,
                    class: 'select2', data: { placeholder: 'Select project' })
+       
+      %span{ data: { toggle: 'tooltip', placement: 'auto top' },
+      title: 'Moving an issue will copy the discussion to a different project and close it here. All participants will be notified of the new location.' }
+        = icon('info-circle')
 
 - if issuable.is_a?(MergeRequest)
   %hr