Setting.__bool__ should forward to the underlying value

[lslunis]

Right now, settings are always considered true when coerced to bool:

if some_setting:
  # always executes

It's easy to forget to call .get(), and rather than raising an error, this silently does the wrong thing. Instead, it should either raise an error or behave as if bool(some_setting.get()) was called.

[lunixbochs]

should be fixed in 1467, please confirm

[lslunis]

Confirmed