Function map_range_through_edits 

pub fn map_range_through_edits(
    range: TextRange,
    edits: &[Edit],
) -> Option<TextRange>

Map a range through a sequence of edits applied left-to-right (the order Edit::apply would run them — each edit is expressed against the text produced by its predecessors). Any single invalidating edit collapses the whole result to None.