join kdocs fixes

Author: AndreiKingsley

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/documentation/AutoRenaming.kt

@@ -0,0 +1,18 @@
+package org.jetbrains.kotlinx.dataframe.documentation
+
+import org.jetbrains.kotlinx.dataframe.DataFrame
+
+/**
+ * ## Auto-renaming in [DataFrame]
+ *
+ * In some operations, multiple columns with the same name may appear
+ * in the resulting [DataFrame].
+ *
+ * In such cases, columns with duplicate names are automatically renamed
+ * using the pattern `"\$name\$n"`, where `name` is the original column name
+ * and `n` is a unique index (1, 2, 3, and so on); the first name column goes without a number.
+ *
+ * It is recommended to [rename][org.jetbrains.kotlinx.dataframe.api.rename] them
+ * to maintain clarity and improve code readability.
+ */
+internal interface AutoRenaming