interface completion tries to import top level type from same class

Open completion at the `|` and accept the `ChildInterface` completion:

```java
public class TestImport implements | {

}

interface TopLevelInterface {
interface ChildInterface {

}
}
```

The result is

```java
import TopLevelInterface.ChildInterface;

public class TestImport implements ChildInterface {

}

interface TopLevelInterface {
interface ChildInterface {

}
}
```

This makes no sense, since you can't import types from the default package, and the type is in the current compilation unit. The correct completion should be:

```java
public class TestImport implements TopLevelInterface.ChildInterface {

}

interface TopLevelInterface {
interface ChildInterface {

}
}
```