BrowserWindow: Add OnBoundsChanged event

While not being an original Electron event, this one includes the bounds values,
saving the additional roundtrip for calling GetBoundsAsync

Author: softworkz

src/ElectronNET.API/API/BrowserWindow.cs

@@ -186,6 +186,19 @@ public event Action OnMove
         remove => RemoveEvent(value, Id);
     }
 
+    /// <summary>
+    /// Emitted when the window is moved or resized.
+    /// </summary>
+    /// <remarks>
+    ///     While not being an original Electron event, this one includes the bounds values,
+    ///     saving the additional roundtrip for calling <see cref="GetBoundsAsync"/>.
+    /// </remarks>
+    public event Action<Rectangle> OnBoundsChanged
+    {
+        add => AddEvent(value, Id);
+        remove => RemoveEvent(value, Id);
+    }
+
     /// <summary>
     /// macOS: Emitted once when the window is moved to a new position.
     /// </summary>