Bug 15208: Ease translation for shelves messages

Bug 15208: Ease translation for shelves messages

This string patch only puts <span>...</span>
around shelves messages. It split a monster
translation string into its components.
This kind of string to translate is error-prone.

Also fixed a typo on opac, 'deleteing'

To test:
1) Search for 'An error occurred when updating this list'
on your preferred language translation file for staff
or opac
(xx-YY-staff-prog.po or xx-YY-opac-bootstrap.po)
You will see a 'big' string to translate

2) Apply the patch

3) Update translation files for your language

4) Search again, big one is gone and there are
new individual strings to translate.

Sorry for not spotting this before string freeze

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>