Function difft::display::hunks::novel_section_in_order

fn novel_section_in_order(
    lhs_novel_mps: &[&MatchedPos],
    rhs_novel_mps: &[&MatchedPos],
    lhs_prev_matched_line: Option<LineNumber>,
    rhs_prev_matched_line: Option<LineNumber>,
    opposite_to_lhs: &HashMap<LineNumber, HashSet<LineNumber>, BuildHasherDefault<FxHasher>>,
    opposite_to_rhs: &HashMap<LineNumber, HashSet<LineNumber>, BuildHasherDefault<FxHasher>>
) -> Vec<(Side, MatchedPos)>

Given a sequence of novel MatchedPos values in a section between two unchanged MatchedPos values, return them in an order suited for displaying.

unchanged-before novel-1
novel-2
novel-3
novel-4 unchanged-after

We need novel-1 to occur before novel-2/3, and novel-2/3 to occur before novel-4, so we can safely interleave LHS and RHS whilst still being monotonically increasing.