Clean up E0507 explanation

Author: GuillaumeGomez

src/librustc_error_codes/error_codes/E0507.md

@@ -1,9 +1,4 @@
-You tried to move out of a value which was borrowed.
-
-This can also happen when using a type implementing `Fn` or `FnMut`, as neither
-allows moving out of them (they usually represent closures which can be called
-more than once). Much of the text following applies equally well to non-`FnOnce`
-closure bodies.
+A borrowed value was moved out.
 
 Erroneous code example:
 
@@ -32,6 +27,11 @@ you have three choices:
 * Somehow reclaim the ownership.
 * Implement the `Copy` trait on the type.
 
+This can also happen when using a type implementing `Fn` or `FnMut`, as neither
+allows moving out of them (they usually represent closures which can be called
+more than once). Much of the text following applies equally well to non-`FnOnce`
+closure bodies.
+
 Examples:
 
 ```