Bug 25879: (follow-up) Update overlooked guarantor markup

Bug 25879: (follow-up) Update overlooked guarantor markup

This patch updates another section of guarantor markup which should have
been updated with the others.

To test, apply the patch and locate an adult patron.

 - Click "Add guarantee"
 - Confirm that the part of the form for adding a guarantee looks
   correct.
 - Confirm that the new patron information is saved correctly.

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>