Indentation fails for strings and integers

The following code is indented as such:

```nix
{
  hello =
    world;

  yes =
  "no";

  pi =
  3;

  x = [
    foo
  "bar"
  42
  ];
}
```

It should be indented as:

```nix
{
  hello =
    world;

  yes =
    "no";

  pi =
    3;

  x = [
    foo
    "bar"
    42
  ];
}
```