Add Unit tests and KDocs for family of generate<Something> methods #1281
Description
We have no proper Unit tests and KDocs for this functionality which will be is highly useful in upcomping release
https://github.com/Kotlin/dataframe/blob/master/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/generateCode.kt
- generateCode
- generateInterfaces
- generateDataClasses