CardView: Update Field Template demo description (#30155)

Author: arman-boyakhchyan

apps/demos/Demos/CardView/FieldTemplate/description.md

@@ -1,4 +1,4 @@
 Field templates allow you to display custom content in field elements. Use the [fieldTemplate](/Documentation/ApiReference/UI_Components/dxCardView/Configuration/columns/#fieldTemplate) property to configure these templates.
 
-In this demo, custom field templates are configured to customize the appearance of the 'Priority', 'Assigned to', and 'Completed' fields.
-<!--split-->
+This demo configures field templates to customize the appearance of the 'Priority', 'Assigned to', and 'Completed' fields. It also adds custom card headers with **cardHeader**.[template](/Documentation/ApiReference/UI_Components/dxCardView/Configuration/cardHeader/#template).
+<!--split-->