Update hello-world.yml (dotnet#31700)

* Update hello-world.yml

Added 'string' in line 64 for the code to copy into the editor

* Update docs/csharp/tour-of-csharp/tutorials/hello-world.yml

Co-authored-by: Bill Wagner <[email protected]>

* Update docs/csharp/tour-of-csharp/tutorials/hello-world.yml

Co-authored-by: Bill Wagner <[email protected]>

Co-authored-by: Bill Wagner <[email protected]>

Author: Chazzersize

docs/csharp/tour-of-csharp/tutorials/hello-world.yml

@@ -60,6 +60,9 @@ items:
     the name to one of your friends. Add these two lines in the interactive window
     following the code you've already added.  Make sure you keep the declaration
     of the `aFriend` variable and its initial assignment.
+    
+    > [!IMPORTANT]
+    > Don't delete the declaration of `aFriend`. Add the code below following the existing declaration.
 
     ```csharp
     aFriend = "Maira";