concestor rather than target HEAD for filter since

[tomdavidson]

fitler since change uses a diff from current branch and I think the HEAD of the target branch.

I think diffing from the concestor is better than the HEAD of the target trunk to ensure the filter is only capturing what is changed in the working branch and not other merged changes since the working branch was created.... I like to use git diff --name-only HEAD $(git merge-base --fork-point HEAD main) -- "$glob"

Does this make more sense to how others are expecting the filter since to work?