Add autocompletion for Pet about pet

[RamiAwar]

Still need to look into this, but I have something working.

ZSH autocompletion template:

# Define completion function for the 'pet' command
_pet_complete() {
    local -a pet_commands=("new" "edit" "search" "exec")

    _arguments -C \
        '1: :->command' \
        '*::arg:->args'

    case $state in
        (command)
            # Complete the command based on the list of commands
            _describe 'command' pet_commands
            ;;
        (args)
            # Do nothing for now, you can add additional completions for command arguments here
            ;;
    esac
}

# Register completion function
_zstyle ':completion:*:pet:*' completer _pet_complete

# Call the completion function
_pet_complete "$@"```