Mark some classes as sealed

Author: Cédric Belin

.github/workflows/ci.yaml

@@ -10,7 +10,7 @@ jobs:
       - name: Set up .NET
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: 8
+          dotnet-version: 9
       - name: Run tests
         run: dotnet test
         env:

src/author.cs

@@ -6,7 +6,7 @@ namespace Belin.Akismet;
 /// Represents the author of a comment.
 /// </summary>
 /// <param name="ipAddress">The author's IP address.</param>
-public class Author(string ipAddress) {
+public sealed class Author(string ipAddress) {
 
 	/// <summary>
 	/// The author's mail address. If you set it to <c>"akismet-guaranteed-spam@example.com"</c>, Akismet will always return <see langword="true"/>.

src/blog.cs

@@ -6,7 +6,7 @@ namespace Belin.Akismet;
 /// Represents the front page or home URL transmitted when making requests.
 /// </summary>
 /// <param name="url">The blog or site URL.</param>
-public class Blog(string url) {
+public sealed class Blog(string url) {
 
 	/// <summary>
 	/// The character encoding for the values included in comments.

src/comment.cs

@@ -4,7 +4,7 @@ namespace Belin.Akismet;
 /// Represents a comment submitted by an author.
 /// </summary>
 /// <param name="author">The comment's author.</param>
-public class Comment(Author author) {
+public sealed class Comment(Author author) {
 
 	/// <summary>
 	/// The comment's author.