Log Message:
py-prompt_toolkit2: updated to 3.0.8

3.0.8:

New features:
- Added `validator` parameter to `input_dialog`.

Fixes:
- Cope with stdout not having a working `fileno`.
- Handle situation when /dev/null is piped into stdin, or when stdin is closed
  somehow.
- Fix for telnet/ssh server: `isatty` method was not implemented.
- Display correct error when a tuple is passed into `to_formatted_text`.
- Pass along WORD parameter in `Document._is_word_before_cursor_complete`.
  Fixes some key bindings.
- Expose `ProgressBarCounter` in shortcuts module.