Add link detail-grid-excel-export-all-pages-all-details project

Author: boyandim

docs/aspnet-mvc/helpers/grid/how-to/excel/detail-grid-export.md

@@ -11,3 +11,6 @@ workbook of the detail grids. The event is prevented to avoid saving an Excel fi
 > This project requires UI for ASP.NET MVC version 2014.3.1125 and up. Earlier versions don't have the `ExcelExport` event exposed via the fluent API.
 
 [Detail Grid Excel Export Visual Studio Project](https://github.com/telerik/ui-for-aspnet-mvc-examples/tree/master/grid/detail-grid-excel-export)
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+[Detail Grid Excel Export All Pages Visual Studio Project](https://github.com/telerik/ui-for-aspnet-mvc-examples/tree/master/grid/detail-grid-excel-export-all-pages-all-details)
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