Clean up E0029

Author: GuillaumeGomez

src/librustc_error_codes/error_codes/E0029.md

@@ -1,8 +1,6 @@
-In a match expression, only numbers and characters can be matched against a
-range. This is because the compiler checks that the range is non-empty at
-compile-time, and is unable to evaluate arbitrary comparison functions. If you
-want to capture values of an orderable type between two end-points, you can use
-a guard.
+Something other than numbers and characters has been used for a range.
+
+Erroneous code example:
 
 ```compile_fail,E0029
 let string = "salutations !";
@@ -20,3 +18,9 @@ match string {
     _ => {}
 }
 ```
+
+In a match expression, only numbers and characters can be matched against a
+range. This is because the compiler checks that the range is non-empty at
+compile-time, and is unable to evaluate arbitrary comparison functions. If you
+want to capture values of an orderable type between two end-points, you can use
+a guard.