Расскажи о типах any, unit и nothing в языке Kotlin.

Any — the root type in the Kotlin class hierarchy. It is the superclass of all classes that do not explicitly inherit from another class. Corresponds to the Object type in Java.

Unit — a type indicating the absence of a meaningful return value. Analogous to void in Java. It is a singleton — only one instance of Unit exists. Functions that do not explicitly specify a return type return Unit by default.

Nothing — a type indicating that a function will never successfully complete (for example, it throws an exception or runs an infinite loop). It can be used as a "bottom" type, being a subtype of any other type. It is used for defining variable types that will never be assigned a value ("dead code").