Add XML Docs for pubternal types

\n\nCommit migrated from dotnet/extensions@033ea04

Author: Pilchie

src/FileProviders/Manifest.MSBuildTask/src/Entry.cs

@@ -8,7 +8,8 @@
 namespace Microsoft.Extensions.FileProviders.Embedded.Manifest.Task.Internal
 {
     /// <summary>
-    /// This type is for internal uses only and is not meant to be consumed by any other library.
+    /// This API supports infrastructure and is not intended to be used
+    /// directly from your code. This API may change or be removed in future releases.
     /// </summary>
     [DebuggerDisplay("{Name,nq}")]
     public class Entry : IEquatable<Entry>

src/Localization/Localization/src/Internal/AssemblyWrapper.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved. 
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
@@ -7,6 +7,10 @@
 
 namespace Microsoft.Extensions.Localization.Internal
 {
+    /// <summary>
+    /// This API supports infrastructure and is not intended to be used
+    /// directly from your code. This API may change or be removed in future releases.
+    /// </summary>
     public class AssemblyWrapper
     {
         public AssemblyWrapper(Assembly assembly)

src/Localization/Localization/src/Internal/IResourceStringProvider.cs

@@ -1,11 +1,15 @@
-// Copyright (c) .NET Foundation. All rights reserved. 
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information. 
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Collections.Generic;
 using System.Globalization;
 
 namespace Microsoft.Extensions.Localization.Internal
 {
+    /// <summary>
+    /// This API supports infrastructure and is not intended to be used
+    /// directly from your code. This API may change or be removed in future releases.
+    /// </summary>
     public interface IResourceStringProvider
     {
         IList<string> GetAllResourceStrings(CultureInfo culture, bool throwOnMissing);

src/Localization/Localization/src/Internal/ResourceManagerStringProvider.cs

@@ -1,5 +1,5 @@
-// Copyright (c) .NET Foundation. All rights reserved. 
-// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information. 
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System.Collections;
 using System.Collections.Generic;
@@ -9,6 +9,10 @@
 
 namespace Microsoft.Extensions.Localization.Internal
 {
+    /// <summary>
+    /// This API supports infrastructure and is not intended to be used
+    /// directly from your code. This API may change or be removed in future releases.
+    /// </summary>
     public class ResourceManagerStringProvider : IResourceStringProvider
     {
         private readonly IResourceNamesCache _resourceNamesCache;