Add missing xml docs for IExceptionHandler (#48814)

Author: divyeshio

src/Middleware/Diagnostics/src/ExceptionHandler/ExceptionHandlerServiceCollectionExtensions.cs

@@ -42,12 +42,12 @@ public static IServiceCollection AddExceptionHandler<TService>(this IServiceColl
     }
 
     /// <summary>
-    /// 
+    /// Adds an `IExceptionHandler` implementation to services. `IExceptionHandler` implementations are used by the exception handler middleware to handle unexpected request exceptions.
+    /// Multiple handlers can be added and they're called by the middleware in the order they're added.
     /// </summary>
-    /// <typeparam name="T"></typeparam>
-    /// <param name="services"></param>
-    /// <returns></returns>
-
+    /// <typeparam name="T">The type of the exception handler implementation.</typeparam>
+    /// <param name="services">The <see cref="IServiceCollection"/> for adding services.</param>
+    /// <returns>The modified <see cref="IServiceCollection"/>.</returns>
     public static IServiceCollection AddExceptionHandler<[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicConstructors)] T>(this IServiceCollection services) where T : class, IExceptionHandler
     {
         return services.AddSingleton<IExceptionHandler, T>();

src/Middleware/Diagnostics/src/ExceptionHandler/IExceptionHandler.cs

@@ -6,16 +6,22 @@
 namespace Microsoft.AspNetCore.Diagnostics;
 
 /// <summary>
-/// 
+/// Represents an interface for handling exceptions in ASP.NET Core applications.
+/// `IExceptionHandler` implementations are used by the exception handler middleware.
 /// </summary>
 public interface IExceptionHandler
 {
     /// <summary>
-    /// 
+    /// Tries to handle the specified exception asynchronously within the ASP.NET Core pipeline.
+    /// Implementations of this method can provide custom exception handling logic for different scenarios. 
     /// </summary>
     /// <param name="httpContext"></param>
     /// <param name="exception"></param>
     /// <param name="cancellationToken"></param>
-    /// <returns></returns>
+    /// <returns>
+    /// A <see cref="ValueTask{TResult}"/> representing the asynchronous handling operation indicating 
+    /// <see langword="true"/> if the exception was
+    /// handled successfully; otherwise <see langword="false"/>.
+    /// </returns>
     ValueTask<bool> TryHandleAsync(HttpContext httpContext, Exception exception, CancellationToken cancellationToken);
 }