Bug 16537 - Overdue and Status triggers grammar

Bug 16537 - Overdue and Status triggers grammar

Test plan:

1) Go to the staff client
2) Click on Tools - Overdue notice/status triggers
3) Confirm that the first sentence reads "a" checkout rather than "an" checkout

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer  <katrin.fischer@bsz-bw.de>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit a589879f495aeb25200119cb4f1bf76c28dce660)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>
(cherry picked from commit 020d755ed061cfc94ca12eace6fae7388cc89e3e)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>