4be7ac930b
^KT-58985 Fixed Review: https://jetbrains.team/p/kt/reviews/10385 `isData` returns `true` for `data object`s even if kotlin-reflect version is old (1.2.0), so it looks like we got correct `KClass.isData` behaviour for "free". That's why this behaviour was never covered with tests. This commit updates the documentation and covers the behaviour described in the KDoc with tests.