fix comment in 'Clone to stasify borrow checker' (#291)

Author: mokurin000

anti_patterns/borrow_clone.md

@@ -17,14 +17,14 @@ let mut x = 5;
 // Borrow `x` -- but clone it first
 let y = &mut (x.clone());
 
-// perform some action on the borrow to prevent rust from optimizing this
-//out of existence
-*y += 1;
-
 // without the x.clone() two lines prior, this line would fail on compile as
 // x has been borrowed
 // thanks to x.clone(), x was never borrowed, and this line will run.
 println!("{}", x);
+
+// perform some action on the borrow to prevent rust from optimizing this
+//out of existence
+*y += 1;
 ```
 
 ## Motivation