Unexected (and inconsistent) insertion conflict on prefix+suffix parameter

While this works:

```rust
router.insert("/a{b}", "1").unwrap();
router.insert("/a{b}/", "2").unwrap();
```

the same routes in different order lead to a conflict:

```rust
router.insert("/a{b}/", "2").unwrap();
router.insert("/a{b}", "1").unwrap();
```