Support Kotlin nested typealiases

[atyrin]

https://github.com/Kotlin/KEEP/blob/context-parameters/proposals/type-aliases.md#nested-type-aliases
https://youtrack.jetbrains.com/issue/KT-45285

Currently, Dokka 2.0.0 ignores those declarations in moth K1/K2 modes.

class BasicTAContainer {
    /**
     * TA has an annotation Deprecated with message
     */
    @Deprecated (message = "test")
    typealias AliasToStringWithDeprecatedAnnotation = String

    class Nested
    /**
     * Alias to [Nested]
     */
    typealias AliasToNested = Nested

    inner class Inner
    typealias AliasToInner = Inner

    object Object
    typealias AliasToObject = Object

    companion object Companion
    typealias AliasToCompanion = Companion

    typealias AliasToFunctionalType = (Int) -> Boolean
    typealias AliasToFunctionalTypeWithGeneric<T> = (T) -> Boolean
}