Tour description doesn't match tour code example

[evmar]

I was reading "A tour of Unison" and found this part:

Now put the following in your scratch file:

square : [Nat](https://share.unison-lang.org/latest/types/@@Nat) -> [Nat](https://share.unison-lang.org/latest/types/@@Nat)
square x =
  use Nat *
  x [*](https://share.unison-lang.org/latest/terms/@@Nat.*) x
This defines a function called
square
.It takes an argument called
x
and it returns
x
multiplied by itself.

The first line,
use .base
,tells Unison that you want to use short names for the base libraries in this file (which allows you to say
[Nat](https://share.unison-lang.org/latest/types/@@Nat)
instead of having to say
base.Nat
).

The lower text mentions use .base, but that is not mentioned in the snippet.