bump to v1.9.6

- v1.9.6
  - fixed: incorrect rune count at calc escaped text in help screen.
    > help screen might not be proper in a small terminal window
  - remove deprecated internal options: `--help-zsh`, `--help-bash`
  - add new option `--man` to enter manpage entry of a sub-command, try `fluent ms tags ls --man`. [linux/darwin only]
  - fixed: Flag.Action return err but cmdr.Exec no breaking its flow.