message: fix wrong method name loadAfdb
diff: if (emdb) viewer.loadEmdb(emdb);
  var afdb = getParam('afdb', '[^&]+').trim();
  - if (afdb) viewer.loadAfdb(afdb);
  + if (afdb) viewer.loadAlphaFoldDb(afdb);
  var modelArchive = getParam('model-archive', '[^&]+').trim();
  if (modelArchive) viewer.loadModelArchive(modelArchive);
  