style fixes

apps/files/js/files.js

apps/files/templates/part.list.php

apps/files_sharing/public.php

core/ajax/preview.php

core/ajax/publicpreview.php

core/ajax/trashbinpreview.php

core/routes.php

lib/helper.php

lib/preview.php

lib/preview/images.php

lib/preview/libreoffice-cl.php

lib/preview/movies.php

lib/preview/mp3.php

lib/preview/msoffice.php

lib/preview/office.php

lib/preview/pdf.php

lib/preview/txt.php

lib/preview/unknown.php

lib/template.php

lib/template/functions.php