Update Creating a new code fix.md (#1331)

Update CodeFix docs

Author: edgarfgp

docs/Creating a new code fix.md

@@ -34,12 +34,12 @@ The unit test file contains a [single focused test](https://github.com/haf/expec
 
 1. Using the `dotnet test` command:
  ```bash
-dotnet test -f net6.0 ./test/FsAutoComplete.Tests.Lsp/FsAutoComplete.Tests.Lsp.fsproj
+dotnet test -f net8.0 ./test/FsAutoComplete.Tests.Lsp/FsAutoComplete.Tests.Lsp.fsproj
  ```
 
 2. Alternatively, using the `dotnet run` command:
  ```bash
-dotnet run -f net6.0 --project ./test/FsAutoComplete.Tests.Lsp/FsAutoComplete.Tests.Lsp.fsproj
+dotnet run -f net8.0 --project ./test/FsAutoComplete.Tests.Lsp/FsAutoComplete.Tests.Lsp.fsproj
  ```
 
 This comprehensive approach ensures that the newly introduced code fix is properly integrated, tested, and ready for seamless integration into the FSAutocomplete environment.