Bug 11225: remove \n from some strings to be translated

Bug 11225: remove \n from some strings to be translated

Some strings in the serials module contain linebreaks \n that cause
problems in translation.

Test plan:
- Update your po file
- Verify that strings in serials/subscription-add.tt and
  serials/subscription-numberpatterns.tt are present and don't contain
  "\n" character.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Template only change, passes all tests and QA script.
Updated po files now contain only the strings and no line breaks.

Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
No regressions found. Passes koha-qa.pl and xt.

Signed-off-by: Galen Charlton <gmc@esilibrary.com>