Temporarily added MudBlazor.Markdown to the solution

This is necessary due to issue https://github.com/MyNihongo/MudBlazor.Markdown/issues/247

I created a PR as well: https://github.com/MyNihongo/MudBlazor.Markdown/pull/246

MudBlazor.Markdown/Services/Registration/ServiceCollectionEx.cs

@@ -0,0 +1,15 @@
+namespace MudBlazor;
+
+public static class ServiceCollectionEx
+{
+	public static IServiceCollection AddMudMarkdownServices(this IServiceCollection @this)
+	{
+		return @this.AddScoped<IMudMarkdownThemeService, MudMarkdownThemeService>();
+	}
+
+	public static IServiceCollection AddMudMarkdownClipboardService<T>(this IServiceCollection @this)
+		where T : class, IMudMarkdownClipboardService
+	{
+		return @this.AddScoped<IMudMarkdownClipboardService, T>();
+	}
+}