MailNotification: fix some english errors and split too long lines
MailNotification: fix some english errors and split too long lines

Signed-off-by: Nicolas Dufresne <36c35e0aac84fcb59b447cc6415df42e7fda8df7@collabora.co.uk>

freedesktop-unofficial-mirror/telepathy__telepathy-spec,TelepathyIM/telepathy-spec