Suggestion to use "is { }" pattern for null checking is wrong.

Take this piece of code:

```
private void OnDrawGizmosSelected()
{
Gizmos.DrawSphere(rb.position, 1.0f);
}
```

*Check expression for null* changes it to this which doesn't work for Unity objects:

```
private void OnDrawGizmosSelected()
{
if (rb is { })
Gizmos.DrawSphere(rb.position, 1.0f);
}
```

Instead it should do this:

```
private void OnDrawGizmosSelected()
{
if (rb != null)
Gizmos.DrawSphere(rb.position, 1.0f);
}
```

Now that's even more problematic because nowhere in the options this can be changed.

JetBrains ReSharper 2020.3 Build 203.0.20201211.113035
Unity Support 2020.3.1.132