Typo in example Arity_T morphism

[kevinclancy]

In Chapter 1, we have the text "Just as we wrote the morphisms in $$\mathbf{Arity}$$ as $$(x_1, x_2 \mapsto x_2, x_1, x_2)$$, we can write the morphisms in $$\mathbf{Arity}_{\mathcal T}$$ as

$$(x_1 : \tau_1, x_2 : \tau_2, x_3 : \tau_2 \mapsto x_2 : \tau_2, x_1 : \tau_1, x_2 : * \tau_1 *)$$

..."

The $$\tau_1$$ at the end should be $$\tau_2$$