removed leftover from 933ebc8 in values-it/strings.xml

the commit 933ebc8504dd154f2b973060033b6fd36dae4bb8 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 #8 from Boris-de/master

fix italian strings.xml