Update Docs

Author: ChrisPulman

README.md

@@ -24,6 +24,7 @@ ReactiveUI Source Generators automatically generate ReactiveUI objects to stream
 - `[IViewFor(nameof(ViewModelName))]`
 - `[RoutedControlHost("YourNameSpace.CustomControl")]`
 - `[ViewModelControlHost("YourNameSpace.CustomControl")]`
+- `[BindableDerivedList]` Generates a derived list from a ReadOnlyObservableCollection backing field
 
 ### Compatibility Notes
 - For ReactiveUI versions **older than V19.5.31**, all `[ReactiveCommand]` options are supported except for async methods with a `CancellationToken`.
@@ -521,6 +522,18 @@ public partial class MyReactiveControl : UserControl
 }
 ```
 
+### Usage ReadOnlyObservableCollection
+
+```csharp
+using ReactiveUI.SourceGenerators;
+
+public partial class MyReactiveClass
+{
+    [BindableDerivedList]
+    private readonly ReadOnlyObservableCollection<string> _myList;
+}
+```
+
 ## Platform specific Attributes
 
 ### WinForms