Updated kubectl bash completion usage in the doc. (#1093)
Updated kubectl bash completion usage in the doc. (#1093)

We have moved the shell script into `kubectl completion` command in [#23801](https://github.com/kubernetes/kubernetes/pull/23801), updated the bash completion usage in the doc.

Fixes #1092
erictune/erictune.github.io,aidevops/kubernetes.github.io,rata/kubernetes.github.io,aidevops/kubernetes.github.io,aidevops/kubernetes.github.io,rata/kubernetes.github.io,aidevops/kubernetes.github.io,erictune/erictune.github.io,aidevops/kubernetes.github.io,rata/kubernetes.github.io,erictune/erictune.github.io,erictune/erictune.github.io,rata/kubernetes.github.io,rata/kubernetes.github.io,erictune/erictune.github.io