Remove stray `use<T>`

We had included one `use<T>` in a pre-migration example when it should
have only appeared in a post-migration example.  Let's fix this error.

(Thanks to @kennytm for pointing this out.)

text/3617-precise-capturing.md

@@ -397,7 +397,7 @@ Note that since generic type parameters must have names to be captured with `use
 
 ```rust
 //@ edition: 2021
-fn foo<'t>(_: &'t (), x: impl Sized) -> impl use<T> Sized { x }
+fn foo<'t>(_: &'t (), x: impl Sized) -> impl Sized { x }
 ```
 
 ...into this: