add `#[test]` attribute to `test/main.rs:710`

self-explanatory

there's a bug in which that test does not have the `#[test]` attribute

```rust
 
fn test_try_into_array() {
    // Inline < capacity
    let vec = SmallVec::<u8, 2>::from_iter(0..1);
    // ...
```

simply add `#[test]`