message: fix: off-by-1 issue in trailing gap number calculation
diff: @@ -50,7 +50,7 @@ GapCounts countGaps(const NucleotideSequence& seq) {
  int leading = begin;
  int internal = totalInternalGaps;
  - int trailing = len - end;
  + int trailing = len - end - 1;
  int total = leading + internal + trailing;
  return GapCounts{
  