fix bad link. (#18641)

The file name was incorrect.

Author: BillWagner

docs/csharp/tutorials/intro-to-csharp/index.md

@@ -23,7 +23,7 @@ You can try these tutorials in different environments. The concepts you'll learn
 - [In your browser, on the docs platform](hello-world.yml): This experience embeds a runnable C# code window in docs pages. You write and execute C# code in the browser.
 - [In the Microsoft Learn experience](https://docs.microsoft.com/learn/paths/csharp-first-steps/). This learning path contains several modules that teach the basics of C#.
 - [In Jupyter on Binder](https://mybinder.org/v2/gh/dotnet/try-samples/master?filepath=hello-csharp%2Fhello-world.ipynb). You can experiment with C# code in a Jupyter notebook on binder.
-- [On your local machine](numbers.md). After you've explored online, you can [download](https://dotnet.microsoft.com/download) the .NET Core SDK and build programs on your machine.
+- [On your local machine](numbers-in-csharp-local.md). After you've explored online, you can [download](https://dotnet.microsoft.com/download) the .NET Core SDK and build programs on your machine.
 
 All the introductory tutorials following the Hello World lesson are available using
 the online browser experience or [in your own local development