"There is no canonised martyr whose last words expressed spite or anger or vengeance."
The Holy Father has mentioned martydom several times since he became Pope. Most likely he will speak about it at today's Mass as well.
To be considered a 'canonical' martyr, certain requirements must be met. For instance, if a guy was crossing the street and was run over and killed by the Nuns on the Bus - either 'accidently' or deliberately (in revenge for making vindictive comments about them), he probably couldn't be considered a martyr.
In fact, to be a martyr, one has to love their enemy...
Thus the Christian martyr does not die out of hatred of the enemy as a soldier might, but out of love for his killers, as Jesus taught and lived (Mt 5:43-48). "No man has greater love than this, to lay down one's life for one's friends" (Jn 15:13), but for the Christian our enemies are also our friends as long as their conversion is possible. After Stephen: St Peter, St Paul, and St James the Apostle (Acts 12:2) were all martyrs, and following them a "great cloud of witnesses" (Heb 12:1). In the liturgy of the Church, special honour is given to the Virgin Martyrs (women and men, Rev 14:4) who are models of both the virtues of chastity and courage. -Read more on the criteria to be a martyr here.