Hudson Clark 78b4472b32
Support pattern matching null literals (#10829)
# Description
Support pattern matching against the `null` literal.  Fixes #10799 

### Before
```nushell
> match null { null => "success", _ => "failure" }
failure
```

### After
```nushell
> match null { null => "success", _ => "failure" }
success
```

# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->
Users can pattern match against a `null` literal.
2023-10-25 06:30:45 +08:00
..