XML comment fixes.

src/Avalonia.Animation/AnimatorKeyFrame.cs

@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel;
+using Avalonia.Animation.Animators;
 using Avalonia.Data;
 using Avalonia.Reactive;
 

src/Avalonia.Base/Platform/IAssetLoader.cs

@@ -65,6 +65,7 @@ namespace Avalonia.Platform
         /// Gets all assets of a folder and subfolders that match specified uri.
         /// </summary>
         /// <param name="uri">The URI.</param>
+        /// <param name="baseUri">The base URI.</param>
         /// <returns>All matching assets as a tuple of the absolute path to the asset and the assembly containing the asset</returns>
         IEnumerable<Uri> GetAssets(Uri uri, Uri baseUri);
     }

src/Skia/Avalonia.Skia/SurfaceRenderTarget.cs

@@ -45,6 +45,7 @@ namespace Avalonia.Skia
         /// <summary>
         /// Create backing Skia surface.
         /// </summary>
+        /// <param name="gpu">GPU.</param>
         /// <param name="width">Width.</param>
         /// <param name="height">Height.</param>
         /// <param name="format">Format.</param>

src/Skia/Avalonia.Skia/WriteableBitmapImpl.cs

@@ -123,6 +123,7 @@ namespace Avalonia.Skia
             /// <summary>
             /// Create framebuffer from given bitmap.
             /// </summary>
+            /// <param name="parent">Parent bitmap impl.</param>
             /// <param name="bitmap">Bitmap.</param>
             public BitmapFramebuffer(WriteableBitmapImpl parent, SKBitmap bitmap)
             {