Problem:
- Progress-events are filtered by "source". But "source" is not required by nvim_echo.
- Without "++nested" (force=false), nvim_echo in an event-handler does not trigger Progress events.
- vim.health does not declare a "source".
Solution:
- Make source mandatory for progress-messages
- Enable ++nested (force=true) by default when firing Progress event.
- Set "source" in vim.health module.
7bf83cc2a6
