Bug 28258: Update bad formatting in AUTO_RENEWALS notice

Bug 28258: Update bad formatting in AUTO_RENEWALS notice

To test:
-Look at the AUTO_RENEWALS notice and see the syntax [% checkout.date_due as_due_date => 1 %]
-Apply patch, updatedatabase
-Look at the AUTO_RENEWALS notice and see the syntax [% checkout.date_due | $KohaDates as_due_date => 1%]

Additional test:
1 - Checkout an item to a patron
2 - Find their borrowernumber, the itemnumber, and the biblionumber
3 - Use the get_prepared_letter script to test the letter content
    perl misc/devel/get_prepared_letter.pl --module circulation --letter-code AUTO_RENEWALS --tables="{\"borrowers\": 5,\"issues\": 1040,\"items\": 1040,\"biblio\": 2 }"

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