Chart: Update Error Bars demo description (DevExpress#30664) (DevExpress#30670)

Author: arman-boyakhchyan

apps/demos/Demos/Charts/ErrorBars/description.md

@@ -1,2 +1,13 @@
-If your data contains an error or measurement uncertainty, you can indicate a confidential interval on the Chart using error bars. To configure them, use the fields of the series’ **valueErrorBar** object. In this example, error bars indicate a range of average temperatures (on the upper pane) and humidity (on the lower pane) for a specific month.
-<!--split-->
+DevExtreme Chart supports value error bars. Implement these bars to indicate data measurement tolerances and [confidence intervals](https://en.wikipedia.org/wiki/Confidence_interval). Configure error bar settings and appearance in the **series**.[valueErrorBar](/Documentation/ApiReference/UI_Components/dxChart/Configuration/series/valueErrorBar/) object.
+
+<!--split-->
+
+To enable error bars, specify one of the following pairs of **valueErrorBar** properties:
+
+- [lowValueField](Documentation/ApiReference/UI_Components/dxChart/Configuration/series/valueErrorBar/#lowValueField) and [highValueField](/Documentation/ApiReference/UI_Components/dxChart/Configuration/series/valueErrorBar/#highValueField)    
+Specify predefined error bars for each series point.
+
+- [value](Documentation/ApiReference/UI_Components/dxChart/Configuration/series/valueErrorBar/#value) and [type](/Documentation/ApiReference/UI_Components/dxChart/Configuration/series/valueErrorBar/#type)    
+Configure dynamically calculated error bars.
+
+This demo implements predefined error bars specified in the Chart data source.