std.Io.Dir: introduce renamePreserve and use it in File.Atomic.link

breaking change: the error for renaming over a non-empty directory now
returns error.DirNotEmpty rather than error.PathAlreadyExists.
ee574f665cAndrew Kelley committed on 1/7/2026, 7:03:37 PMparent8e1850e
11 files changedLine totals unavailable