Sorry FrDavid for disagreeing with a trained man of the cloth. There is a slight difference.
Yes, liturgically (from the point of view of Mass celebrations), Lent ends with the start of the Holy Thursday mass with the Triduum being a mini-session in its own right.
But, for the purposes of the Lenten fast, the 40 days of Lent run from Ash Wednesday to Holy Saturday, not counting the Sundays (in days gone past when the rules of Lenten fast were much more severe than today, the Church was nice enough to give some relief on Sundays).
So, if you had been giving up chocolates for Lent this year, the sacrifice should continue all the way until Jesus rise from the dead. Stopping your sacrifice before the climax just doesn’t make sense as you will then not be accompanying Jesus in his darkest hours.