remove "theory" in "bicartesian closed category theory" (#249)

src/content/1.9/function-types.tex

@@ -401,7 +401,7 @@ \section{Exponentials and Algebraic Data Types}
 the scheme of algebraic data types. It turns out that all the basic
 identities from high-school algebra relating numbers zero and one, sums,
 products, and exponentials hold pretty much unchanged in any bicartesian
-closed category theory for, respectively, initial and final objects,
+closed category for, respectively, initial and final objects,
 coproducts, products, and exponentials. We don't have the tools yet to
 prove them (such as adjunctions or the Yoneda lemma), but I'll list them
 here nevertheless as a source of valuable intuitions.