revlog: allow to pass an existing docket to `_loadindex()` This will be when switching undelying files, for examples during censors and strip operation with rvlog-v2. Differential Revision: https://phab.mercurial-scm.org/D10800

from typing import (
    List,
)

version: int

class mpatchError(Exception): ...

def patches(text: bytes, bins: List[bytes]) -> bytes: ...
def patchedsize(orig: int, data: bytes) -> int: ...