Add Comment Rule Option in ETL

When building out rules in ETL, the documentation (Description/Comments fields) are only available at the rule level. If we have a string of rules that all go together, there isn't a great place to add in comments about what they are going to do, what order they need to be in, etc.

What we have been doing is creating fake Update/Insert rules and marking them as inactive, and then putting in a comment to describe what the series of rules below it will do. It would be nice to be able to explicitly maintain a Comment rule whose only purpose is to provide documentation - i.e. similar to text lines on a BOM.