False positive `KDOC_WITHOUT_RETURN_TAG` for functions returning `Unit` (implicit) or `Nothing` (explicit)

DiKTat should require no @return tags in KDoc comments for expression-body functions with an implicit Unit or an explicit Nothing return types. In the below cases, a KDoc without any @return tag is sufficient:

/**
 * This function does nothing.
 */
fun f1() = Unit

/**
 * This function does nothing.
 */
fun f2() = kotlin.Unit

/**
 * This function fails immediately.
 */
fun fail1(): Nothing = TODO()

/**
 * This function fails immediately.
 */
fun fail2(): kotlin.Nothing = TODO()

Environment information

• diktat version: 1.2.0
• build tool (maven/gradle): Maven
• how is diktat run (CLI, plugin, etc.): Maven plug-in
• kotlin version: 1.7.0
• operating system: Windows