Bug 16214: Fix typo 'To.jon' -> 'To.json'

Bug 16214: Fix typo 'To.jon' -> 'To.json'

Bug 15722 introduces a regression in serials patron search results,
causing the surname to not be displayed

To reproduce:
1. Create a routing list for a subscription
2. Click on "Add recipients" button
3. Run a search
4. Check that surname is not displayed

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>
(cherry picked from commit e916ded09756ba4902a25e9e68fe536614419c87)
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>