fix: update deprecation message for DataRow.get method

 The deprecation message for `DataRow.get(ColumnReference)` was updated to inform users about switching to `col[row]`, especially in the context of `perRowCol`. The code changes were successfully implemented, but the project build failed due to an external dependency issue unrelated to the code updates.

Author: jetbrains-junie[bot]

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/DataRow.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlinx.dataframe.impl.columnName
 import org.jetbrains.kotlinx.dataframe.impl.owner
 import org.jetbrains.kotlinx.dataframe.impl.toIterable
 import org.jetbrains.kotlinx.dataframe.util.DEPRECATED_ACCESS_API
+import org.jetbrains.kotlinx.dataframe.util.DEPRECATED_DATA_ROW_COLUMN_REFERENCE_GET
 import kotlin.reflect.KProperty
 
 /**
@@ -29,7 +30,7 @@ public interface DataRow<out T> {
 
     public operator fun <R> get(expression: RowExpression<T, R>): R = expression(this, this)
 
-    @Deprecated(DEPRECATED_ACCESS_API)
+    @Deprecated(DEPRECATED_DATA_ROW_COLUMN_REFERENCE_GET)
     @AccessApiOverload
     public operator fun <R> get(column: ColumnReference<R>): R
 

core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/util/deprecationMessages.kt

@@ -209,6 +209,9 @@ internal const val UNIFIED_SIMILAR_CS_API = "Deprecated duplicated functionality
 internal const val DEPRECATED_ACCESS_API =
     "It's recommended to migrate to the String or Extension Properties Access API https://kotlin.github.io/dataframe/apilevels.html"
 
+internal const val DEPRECATED_DATA_ROW_COLUMN_REFERENCE_GET =
+    "Accessing a DataRow by ColumnReference (row[col]) is deprecated. Prefer String or extension property access (e.g., row[\"name\"] or row.name). In perRowCol { row, col -> ... }, use the reverse indexing col[row], which remains supported. See https://kotlin.github.io/dataframe/apilevels.html"
+
 internal const val IDENTITY_FUNCTION = "This overload is an identity function and can be omitted."
 
 internal const val COL_REPLACE = "col"