[feature] Shell completion

For zsh, the following script can work:

#compdef interactively

_arguments -s -S \
  "(- : *)"{-h,--help}"[Show list of command-line options]" \
  "--name[Show list of command-line options]: :{_command_names -e}" \
  '(-)1: :{_command_names -e}' \
  '*:: :_normal'

However, it needs #3.

If you can create a PR for #3 that addresses the issues I mentioned, then I think this can be added.