Specific Shift Information in Bell Notifications

When a bell notification is sent for when a volunteer signs up for a shift, it is only a generic message that says something like, "X signed up for a shift in [Opportunity]." It would be much more helpful to have the date, time, and role that the volunteer selected in that notification instead of needing to search the schedule.

This is already the case for when a volunteer removes themselves from a shift, where it shares exactly where the schedule was altered.