Grids: add a note about repainting changes (DevExpress#6876) (DevExpress#6880)

Author: vladaskorohodova

api-reference/10 UI Components/GridBase/3 Methods/cellValue(rowIndex_dataField_value).md

@@ -15,6 +15,8 @@ The [data field](/api-reference/_hidden/GridBaseColumn/dataField.md '{basewidget
 The cell's new value.
 
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+{WidgetName} re-renders the entire row or edit form after the **cellValue** method changes a cell value. To re-render only the modified cell or form item editor, enable [repaintChangesOnly]({basewidgetpath}/Configuration/#repaintChangesOnly).
+
 Call [saveEditData()](/api-reference/10%20UI%20Components/GridBase/3%20Methods/saveEditData().md '{basewidgetpath}/Methods/#saveEditData') after this method to save the changes:
 
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