'Task marked complete' notification email includes the entire page

Steps to Reproduce

1. Create a page with lots of content (~100 lines)
2. Add some Inline tasks to it
3. Save it
4. Mark one of the tasks complete
5. Observe that you receive a notification containing the entire page

This can cause outages (OutOfMemory or GC Overhead) if the page is large and there are multiple tasks and multiple watchers.