Remove trailing \n on a few ts() strings

#: CRM/Event/Cart/Form/Checkout/Payment.php
msgid ""
"There was an error creating a contribution record for your event. Please "
"report this error to the webmaster. Details: %1\n"
msgstr ""

1. templates/CRM/Contribute/Form/ContributionPage/Tab.hlp
   {ts}

   if you need to review, modify or create profiles (you can come back at any time to select or update the Profile(s) used for this page).