undo-files: cleanup legacy files when applicable
The "journal" code is much more compact in 6.4, and so is the "undo" files as a
result. However the previous version were much noisier, so let us cleanup undo
files from older version too.
from typing import (
List,
)
version: int
class mpatchError(Exception): ...
def patches(text: bytes, bins: List[bytes]) -> bytes: ...
def patchedsize(orig: int, data: bytes) -> int: ...