Order of steps is not correct

[mthmulders]

In part 3, step 2 of the step-by-step guide, we write

Run cargo run -- --help; the -- separates arguments for cargo run from the arguments we want to pass to our program; otherwise, --help would've been passed to cargo run. The output should provide a short manual for our future users!

This is not true. The code change to make that happen (adding let cli = Cli::parse();) is given one step later, in step 3.