message: fixed `addUnitPositiveCharges`
diff: @@ -81,12 +81,6 @@ function addUnitPositiveCharges(structure: Structure, unit: Unit.Atomic, builder
  addedElements.clear()
  for (let j = start as StructureElement.UnitIndex; j < end; ++j) {
  - builder.startState()
  - if (typeSymbol(unit, j) === Elements.N) {
  - builder.pushMember(x[elements[j]], y[elements[j]], z[elements[j]], j)
  - }
  - builder.finishState(FeatureType.PositiveCharge, FeatureGroup.None)
  -
  let group = FeatureGroup.None
  if (isGuanidine(structure, unit, j)) {
  group = FeatureGroup.Guanidine
  