docs: add missing `--talosconfig` parameter to end of Hetzner guide

[holly-hacker]

Pull Request

What? (description)

The last command of the Hetzner platform guide was missing the --talosconfig flag which would make the CLI connect to a local cluster, which is incorrect in this context.

Why? (reasoning)

The current command doesn't work :)

Acceptance

Please use the following checklist:

• [ ] you linked an issue (if applicable)
• [ ] you included tests (if applicable)
• [ ] you ran conformance (make conformance)
• [ ] you formatted your code (make fmt)
• [ ] you linted your code (make lint)
• [ ] you generated documentation (make docs)
• [ ] you ran unit-tests (make unit-tests)

See make help for a description of the available targets.

[holly-hacker]

I'm unsure if I'm supposed to write a dummy commit body here to make the workflow pass, I can't find any instructions in CONTRIBUTING.md or the documentation on what I'm supposed to do here. I'm fine with a maintainer creating their own PR with these changes if they want.

[smira]

/m