docs(TensorProduct/Tower): fix doc string of `AlgebraTensorModule.ass…

…oc` (#10051)

Matches variable names in the doc string with the variables used in the type signature of `AlgebraTensorModule.assoc`.

Mathlib/LinearAlgebra/TensorProduct/Tower.lean

@@ -341,7 +341,7 @@ variable [Algebra A B] [IsScalarTower A B M]
 
 /-- Heterobasic version of `TensorProduct.assoc`:
 
-Linear equivalence between `(M ⊗[A] N) ⊗[R] P` and `M ⊗[A] (N ⊗[R] P)`.
+`B`-linear equivalence between `(M ⊗[A] P) ⊗[R] Q` and `M ⊗[A] (P ⊗[R] Q)`.
 
 Note this is especially useful with `A = R` (where it is a "more linear" version of
 `TensorProduct.assoc`), or with `B = A`. -/