Step 1: non-fast-forward error (incorrect solution in tutorial)

The solution for resolving the `non-fast-forward` error in Carbon Tutorial Angular Step 1 is incorrect or misleading.

The user must `git push origin angular-step-1 --force`, other wise following the `git pull upstream angular-step-1` will delete all files in your local `angular-step-1` branch and leave you in a `angular-step-1|MERGE` (resolve conflict) state that contains no conflicts to resolve.

Start with the Carbon Tutorial Angular Step 1 instructions and locate the solution for the non-fast-forward error. Reproduce the reported branch commands, then update the tutorial so the required force-push and subsequent pull steps are accurate. Done means following the documented solution no longer deletes local files or leaves an unexplained merge state.

Written by the indexing model from the issue text.