readme .net 6 updates for razor pages and mvc

Author: christiannagel

3_Web/RazorAndMVC/Readme.md

@@ -11,6 +11,12 @@ This chapter contains these samples:
 * EventViews (view components library)
 * MVCSample (ASP.NET Core MVC Project)
 
+## .NET 6 Updates
+
+With .NET 6, the `Startup` class has been replaced by top-level statements in the *Program.cs* file. The new `WebApplication` class abstracts the use of the `Host` class.
+
+## More Information
+
 For code comments and issues please check [Professional C#'s GitHub Repository](https://github.com/ProfessionalCSharp/ProfessionalCSharp2021)
 
 Please check my blog [csharp.christiannagel.com](https://csharp.christiannagel.com "csharp.christiannagel.com") for additional information for topics covered in the book.