Invalid indent when exclude AddMissingCurlyBraces

I have this phpfmt settings:
```JSON
"phpfmt.exclude": [
    "AddMissingCurlyBraces"
]
```

And I want to format this code:
```PHP
if ($a == null)
  $a = 1;
```

Expected result:
```PHP
if ($a == null)
    $a = 1;
```

Actual result:
```PHP
if ($a == null)
$a = 1;
```

The indentation is always on the same level like the if statement.