Add a description/message to filter subscription emails

We have a number filter subscription to alert a user of overdue tasks or impending events, and a courtesy message would be extremely helpful. It could provide the user information so they do not need to decipher the filter and ultimately, the purpose of the subscription in question.

It would be in the form of an optional description/message when creating/editing a filter subscription. The message could show up as a field just below the subscriber (user) in the email. Simple text (or HTML) should be used.