Problem:
vim.fs.dir() and vim.fs.find() drop errors returned by uv.fs_scandir().
Solution:
- vim.fs.dir():
- Return root scan failures as a secondary return value.
- Propagate recursive scan failures through the iterator. This allows
callers to distinguish unreadable directories from empty ones.
- vim.fs.find(): Collect errors during search, and return the list as
a second retval.
4e04dff228