fix: do not auto clean up buffers after session restore, unless opted in

[cseickel]

fixes #778

This moves the session cleanup functionality to an opt-in feature instead of enabling it automatically for everyone.

The new config option is:

  auto_clean_after_session_restore = false, -- Automatically clean up broken neo-tree buffers saved in sessions

I also moved the first cleanup action from the renderer to the setup function.

[cseickel]

@nhat-vo Can you test this out and confirm it still works as expected when you opt-in to the functionality by setting auto_clean_after_session_restore = false, in your config?

Also, let me know if you think that is a good name for the config option.

[nhat-vo]

@cseickel looks good to me. Thanks a lot for adding the fix! I just want to note, though, that #771 should make neo-tree clean only invalid buffers. Anyway, as there has been quite a few issues regarding this, I think it would be wise to set this option to avoid any further problems.

[cseickel]

Thanks for confirming @nhat-vo.

After thinking about this, I realize that any new functionality needs to be opt-in because you never now how it may interact with all of the different setups people have, especially when doing something like deleting buffers with an autocmd. Even if the default value is eventually true, you still need an escape hatch for people to be able to disable it when they need to.