A type alias may still be inherited from. For example:
```
sealed class MyClass
typealias T = MyClass
class Inheritor : T() // `Inheritor` is a direct inheritor of `MyClass`.
```
The index is a simplified version of the IDE's
`KotlinTypeAliasByExpansionShortNameIndex`, but it should be sufficient
for virtually all cases.
^KT-66013
Marco Pennekamp
a9d7b0c595