message: Fix integer narrowing (from int64) warning.
diff: @@ -82,8 +82,9 @@ LineNumberSet DiffEditsToAddedLineNumbers(const Edits& edits) {
  LineNumberSet added_lines;
  for (const auto& edit : edits) {
  if (edit.operation == Operation::INSERT) {
  - // Add 1 to cover from 0-indexed to 1-indexed.
  - added_lines.Add({edit.start + 1, edit.end + 1});
  + // Add 1 to convert from 0-indexed to 1-indexed.
  + added_lines.Add(
  + {static_cast<int>(edit.start) + 1, static_cast<int>(edit.end) + 1});
  }
  }
  return added_lines;
  