Merge branch 'bash-completion-command-lsblk' of https://github.com/akinomyoga/util...

* 'bash-completion-command-lsblk' of https://github.com/akinomyoga/util-linux:
  bash-completion: use "command ls" instead of "\ls"
  bash-completion: prefix "command" to other external commands
  bash-completion: prefer "builtin cd" to "cd" to avoid aliases
  bash-completion: prefer "command lsblk" to "lsblk" to avoid aliases