Have followers be notified when the Issue or Task is closed

Followers added to a Task or Issue by default are only notified on "Discussion" events.

To have them notified on "Issue Closed", for example:

• Go to Settings > Technical > Email > Subtypes
• Locate the "Issue Started" Message Type for the "project.issue" Model
• Set "Default" to True.

From now on, when users are added as followers to an Issue, the "Issue Started" flag will be marked by default, and they will be notified when the Issue is closed.