Bug 33968: Add missing colons to guarantor related labels

Bug 33968: Add missing colons to guarantor related labels

Fixes some inconsistencies with the labels on the
patron detail page and patron edit form.

To test:
* Activate AllowStaffToSetCheckoutsVisibilityForGuarantor
  and AllowStaffToSetFinesVisibilityForGuarantor system
  preferences
* Link a patron to a guarantor
* Verify on the details tab the options for showing fines
  and checkouts show and are missing colons on the label
* Edit the patorn and verify the same is true for the form
* Apply patch
* Verify missing colons have been added :)

Signed-off-by: Sally <sally.healey@cheshiresharedservices.gov.uk>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>