python-packages: prompt_toolkit -> 0.40

Fixes:
- Fix in output_screen_diff: reset correctly.
- Ignore flush errors in vt100_output.
- Implemented <num>gg Vi key binding.
- Bug fix in the renderer when the style changes.

New features:
- TokenListControl can now display the cursor somewhere.
- Added SwitchableValidator class.
- print_tokens function added.
- get_style argument for Application added.
- KeyBindingManager got an enable_all argument.

Backwards incompatible changes:
- history_search is now a SimpleFilter instance.