feat(DevTools): Shows the property type and the type assigned to the property in a single or split column.

src/Avalonia.Diagnostics/Diagnostics/ViewModels/PropertyViewModel.cs

@@ -24,6 +24,9 @@ namespace Avalonia.Diagnostics.ViewModels
         public abstract bool? IsAttached { get; }
         public abstract void Update();
         public abstract string PropertyType { get; }
+        public string Type => PropertyType == AssignedType
+            ? PropertyType
+            : $"{PropertyType} {{{AssignedType}}}";
 
 
         protected static string GetTypeName(Type type)

src/Avalonia.Diagnostics/Diagnostics/Views/ControlDetailsView.xaml

@@ -33,7 +33,14 @@
         <DataGrid.Columns>
           <DataGridTextColumn Header="Property" Binding="{Binding Name}" IsReadOnly="True" />
           <DataGridTextColumn Header="Value" Binding="{Binding Value}" />
-          <DataGridTextColumn Header="Assinged Type" Binding="{Binding AssignedType}" IsReadOnly="True"/>
+          <DataGridTextColumn Header="Type" Binding="{Binding Type}"
+                              IsReadOnly="True"
+                              IsVisible="{Binding !$parent[UserControl;2].DataContext.ShowDettailsPropertyType}"
+                              />
+          <DataGridTextColumn Header="Assinged Type" Binding="{Binding AssignedType}"  
+                              IsReadOnly="True"
+                              IsVisible="{Binding $parent[UserControl;2].DataContext.ShowDettailsPropertyType}"
+                              />
           <DataGridTextColumn Header="Property Type" Binding="{Binding PropertyType}" 
                               IsReadOnly="True"
                               IsVisible="{Binding $parent[UserControl;2].DataContext.ShowDettailsPropertyType}"

src/Avalonia.Diagnostics/Diagnostics/Views/MainView.xaml

@@ -16,7 +16,7 @@
           </MenuItem.Icon>
         </MenuItem>
         <MenuItem Header="_Dettails">
-          <MenuItem Header="Show Property Type" Command="{Binding ToggleShowDettailsPropertyType}">
+          <MenuItem Header="Split Property Type" Command="{Binding ToggleShowDettailsPropertyType}">
             <MenuItem.Icon>
               <CheckBox BorderThickness="0"
                         IsChecked="{Binding ShowDettailsPropertyType}"