Bug 35221: TrackLastPatronActivityTriggers description is misleading

Bug 35221: TrackLastPatronActivityTriggers description is misleading

This patch updates the description for the TrackLastPatronActivityTriggers system preference to specify that each time an action occurs, the date last seen is updated, as opposed to once per day.

This patch also uniformizes the options and corrects terminology for
checking in/returning.

To test:
1. Apply patch
2. Go to Administration > System preferences
3. Search for TrackLastPatronActivityTriggers
4. Read the description, make sure it makes sense and the spelling and
   grammar are correct
5. Open the drop down of options, make sure the spelling and grammar are
   correct

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>