Bug 33237: Add display of which language default language is expected

Bug 33237: Add display of which language default language is expected

This patch adds the display of 'Default language' to the 'Default'
language in the notices editor tool.

This is so that librarians know which language they are expected to be
writing the notice in so we can remain consistent in both template and
include language used.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>