dirstate-entry: add `modified` property
This was already done in the Rust implementation and is a useful primitive.
The C implementation had this called `merged`, but wasn't used anywhere.
It will be used in the next changeset.
# extension to emulate interrupting filemerge._filemerge
from mercurial import (
error,
extensions,
filemerge,
)
def failfilemerge(*args, **kwargs):
raise error.Abort(b"^C")
def extsetup(ui):
extensions.wrapfunction(filemerge, 'filemerge', failfilemerge)