Bug 16806: no error message for 'too_soon' renewal

To test:
-  for a particular item type & patron category, configure a non-zero
"no renewal before" date so items can't be immediately renewed
- sign in as a patron in aforementioned patron category
- check out an item of aforementioned item type
- go to your renewals page in OPAC /cgi-bin/koha/opac-user.pl
- an error messages appears in the div.alert.dialog up top

Sponsored-by: California College of the Arts
Signed-off-by: Brendon Ford <brendon.ford@manhattan.edu>

Signed-off-by: Irma Birchall <irma@calyx.net.au>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
(cherry picked from commit aa2f56fa1a)
Signed-off-by: Frédéric Demians <f.demians@tamil.fr>

koha-tmpl/opac-tmpl/bootstrap/en/modules/opac-user.tt

@@ -92,6 +92,8 @@ Using this account is not recommended because some parts of Koha will not functi
                                         Your account has expired. Please contact the library for more information.
                                     [% ELSIF error == 'too_many' %]
                                         You have renewed this item the maximum number of times allowed.
+                                    [% ELSIF error == 'too_soon' %]
+                                        It is too soon after the checkout date for this item to be renewed.
                                     [% ELSIF error == 'on_reserve' %]
                                         This item is on hold for another patron.
                                     [% END %]