Bug 34071: Change the phrasing of 'automatic checkin' to fit consistent terminology

Bug 34071: Change the phrasing of 'automatic checkin' to fit consistent terminology

This patch simply changes 'Automatic checkin' to be 'Automatic
check-in'.

Test plan:
1) Go to administration -> item types and click the edit button on an
   item.
2) Notice there is a checkbox labeled 'Automatic checkin'.
3) Apply patch.
4) Refresh the page and notice the checkbox now says 'Automatic
   check-in'.
5) prove t/db_dependent/Koha/Checkouts.t
6) Sign-off :)

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>