internal: fix incorrect offset on multiple indel

[A4-Tacks]

No description provided.

[ChayimFriedman2]

This looks correct to me; this function should return the new location of offset. if indel.delete.start() >= offset, it means we've already passed it so we should return what we've accumulated.

OTOH the return None in the next branch looks incorrect to me - it'll lead to early-exit when we shouldn't just because the next indel doesn't came yet. It should be if indel.delete.contains(offset).

View changes since the review

[A4-Tacks]

This is actually this:

if indel.delete.start() < offset {
    if offset < indel.delete.end() {
        return None; // indel.delete.start() < offset && offset < indel.delete.end()
    }
    res += TextSize::of(&indel.insert);
    res -= indel.delete.len();
}

But I agree that the readability is very low

[ChayimFriedman2]

Right, I got confused.