message: allow MET.SD as metal binding partner
diff: @@ -94,7 +94,7 @@ function addMetalBinding(structure: Structure, unit: Unit.Atomic, builder: Featu
  dative = true
  ionic = true
  }
  - } else if (element === Elements.S && 'CYS' === resname) {
  + } else if (element === Elements.S && (resname === 'CYS' || resname === 'MET')) {
  dative = true
  ionic = true
  } else if (element === Elements.N) {
  