Clean up and document CollectionImageProvider.cs

Emby.Server.Implementations/Collections/CollectionImageProvider.cs

@@ -1,5 +1,3 @@
-#pragma warning disable CS1591
-
 using System.Collections.Generic;
 using System.Linq;
 using Emby.Server.Implementations.Images;
@@ -15,8 +13,18 @@ using MediaBrowser.Model.IO;
 
 namespace Emby.Server.Implementations.Collections
 {
+    /// <summary>
+    /// A collection image provider.
+    /// </summary>
     public class CollectionImageProvider : BaseDynamicImageProvider<BoxSet>
     {
+        /// <summary>
+        /// Initializes a new instance of the <see cref="CollectionImageProvider"/> class.
+        /// </summary>
+        /// <param name="fileSystem">The filesystem.</param>
+        /// <param name="providerManager">The provider manager.</param>
+        /// <param name="applicationPaths">The application paths.</param>
+        /// <param name="imageProcessor">The image processor.</param>
         public CollectionImageProvider(
             IFileSystem fileSystem,
             IProviderManager providerManager,
@@ -48,13 +56,10 @@ namespace Emby.Server.Implementations.Collections
 
                     var episode = subItem as Episode;
 
-                    if (episode != null)
+                    var series = episode?.Series;
+                    if (series != null && series.HasImage(ImageType.Primary))
                     {
-                        var series = episode.Series;
-                        if (series != null && series.HasImage(ImageType.Primary))
-                        {
-                            return series;
-                        }
+                        return series;
                     }
 
                     if (subItem.HasImage(ImageType.Primary))