Bug 10002 - Don't include line breaks in strings that are translated

Bug 10002 - Don't include line breaks in strings that are translated

Several JS alert messages contain "\n" which is problematic for
translation. This patch removes those instances (a line break is not
strictly necessary anyway). Also corrected: two instances of "holds(s)"

To test, place a hold on a title with items. From the biblio detail page
choose Edit -> Delete all items and Edit -> Delete record. In each case
you should see error messages with no line breaks and no misspellings.

Delete all items attached to the record with holds from the item edit
page. Go back to the detail page and choose Edit -> Delete record. You
should see an error message about existing hold(s) with no line breaks
or misspellings.

Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Harmless change, fixes misspellings and makes translations easier

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>