C# implementation of Peter Norvig’s spelling corrector - unfortunately his URL is out of date and shows http://www.anotherchris.net/csharp/how-to-write-a-spelling-corrector-in-csharp/
See the blog post for full details: https://yetanotherchris.dev/csharp/how-to-write-a-spelling-corrector-in-csharp/