Automatic merge from submit-queue (batch tested with PRs 50229, 50973, 50976, 51085, 51084)

Remove duplicate command example

**What this PR does / why we need it**:

`kubectl port-forward --help` currently contains a duplicate example. This PR removes the duplicate.

```release-note
/release-note Remove duplicate command example from `kubectl port-forward --help`
```

/sig cli
/kind cleanup
/kind documentation