Improve documentation regarding runner unregistration
What does this MR do?
This MR tries to improve the documentation around the unregistration of runners.
Why was this MR needed?
The distinction between runners and runner managers is not yet clear to users, so even when they create a runner in the UI, they expect gitlab-runner unregister will delete the runner completely. Instead it will only delete the runner manager that was attached to the runner in gitlab-runner register. So they are surprised that if they restart the runner with the same config.toml, the runner will again accept jobs.
What's the best way to test this MR?
- https://main-runner-4338.docs.gitlab-review.app/runner/register/
- https://main-runner-4338.docs.gitlab-review.app/runner/commands/#gitlab-runner-unregister