removing unused imports

Author: Jolanrensen

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/typeConversions.kt

@@ -20,11 +20,9 @@ import org.jetbrains.kotlinx.dataframe.columns.ColumnSet
 import org.jetbrains.kotlinx.dataframe.columns.FrameColumn
 import org.jetbrains.kotlinx.dataframe.columns.SingleColumn
 import org.jetbrains.kotlinx.dataframe.columns.ValueColumn
-import org.jetbrains.kotlinx.dataframe.documentation.DocumentationUrls
 import org.jetbrains.kotlinx.dataframe.impl.DataRowImpl
 import org.jetbrains.kotlinx.dataframe.impl.GroupByImpl
 import org.jetbrains.kotlinx.dataframe.impl.anyNull
-import org.jetbrains.kotlinx.dataframe.impl.api.convertToDataFrame
 import org.jetbrains.kotlinx.dataframe.impl.asList
 import org.jetbrains.kotlinx.dataframe.impl.columnName
 import org.jetbrains.kotlinx.dataframe.impl.columns.ColumnAccessorImpl