Merge pull request #5580 from AvaloniaUI/set-content-attribute-on-DataGridTemplateColumn

make cell template the content of DataGridTemplateColumn

src/Avalonia.Controls.DataGrid/DataGridTemplateColumn.cs

@@ -8,6 +8,7 @@ using Avalonia.Controls.Utils;
 using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Media;
+using Avalonia.Metadata;
 using Avalonia.Utilities;
 
 namespace Avalonia.Controls
@@ -22,6 +23,7 @@ namespace Avalonia.Controls
                 o => o.CellTemplate,
                 (o, v) => o.CellTemplate = v);
 
+        [Content]
         public IDataTemplate CellTemplate
         {
             get { return _cellTemplate; }