Unable to get the typealias after resolving a reference

[ting-yuan]

When resolving a reference to a type alias, the underlying type is returned instead of the alias. This makes type checking much easier. However, the type alias is skipped and cannot be obtained. Something like KSType.alias: KSTypeAlias? is needed.

[ting-yuan]

Fixed in android/kotlin#74. References are resolved to the closest alias. This is more intuitive and performance should be fine, since the aliases are already resolved and subsequent resolutions should be fast. If there are corner cases that have performance issues, a cache can be implemented in KSP as well, without changing the API.