`#check (0 + 5 + 0) rewrite_by simp only [add_zero]` does not produce `0 + 5`

[Seasawher]

in Optimizing Array Expressions, it says that

#check (0 + 5 + 0) rewrite_by simp only [add_zero]

produces 0 + 5. but actually,

/-
5 : Nat
-/
#check (0 + 5 + 0) rewrite_by simp only [Nat.add_zero]