Fix the reversed suggestion message of `stable_sort_primitive`.
Now Clippy emits `stable_sort_primitive` warning as follows:
```
warning: used sort instead of sort_unstable to sort primitive type `usize`
--> src\asm.rs:41:13
|
41 | self.successors.sort();
| ^^^^^^^^^^^^^^^^^^^^^^ help: try: `self.successors.sort_unstable()`
|
= note: `#[warn(clippy::stable_sort_primitive)]` on by default
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#stable_sort_primitive
```
I think the position of `sort` and `sort_unstable` in the first line should be reversed.
changelog: Fix the reversed suggestion message of `stable_sort_primitive`.