removed leftover from 4dd5a248b154 in values-it/strings.xml

the commit 4dd5a248b154a9aa661c69e17fa3446482991b31 removed the
"twitter_hint" everywhere, but in values-it/strings.xml this string was
multiline, so that the xml is invalid now which prevents the build
Merge pull request #6 from Boris-de/master

fix italian strings.xml