## Summary
Implement
[`no-isinstance-type-none`](https://github.com/dosisod/refurb/blob/master/refurb/checks/builtin/no_isinstance_type_none.py)
as `isinstance-type-none` (`FURB168`).
Auto-fixes calls to `isinstance` to check if an object is `None` to a
`None` identity check. For example,
```python
isinstance(foo, type(None))
```
becomes
```python
foo is None
```
Related to #1348.
## Test Plan
`cargo test`
---------
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
