Fix #6269 - Render LOCAL_DOMAIN as unicode in presentational views (#6305)

app/helpers/instance_helper.rb

@@ -6,6 +6,6 @@ module InstanceHelper
   end
 
   def site_hostname
-    Rails.configuration.x.local_domain
+    @site_hostname ||= Addressable::URI.parse("//#{Rails.configuration.x.local_domain}").display_uri.host
   end
 end