Clean newlines

src/doc/trpl/references-and-borrowing.md

@@ -363,7 +363,7 @@ note: reference must be valid for the block suffix following statement 0 at
     let y: &i32;
     let x = 5;
     y = &x;
-    
+
     println!("{}", y);
 }
 
@@ -371,7 +371,7 @@ note: ...but borrowed value is only valid for the block suffix following
 statement 1 at 3:14
     let x = 5;
     y = &x;
-    
+
     println!("{}", y);
 }
 ```