Replace legacy syntax for each...in with for...of

components/zotero-protocol-handler.js

@@ -596,7 +596,7 @@ function ZoteroProtocolHandler() {
 						var search = new Zotero.Search();
 						search.setScope(s);
 						var groups = Zotero.Groups.getAll();
-						for each(var group in groups) {
+						for (let group of groups) {
 							search.addCondition('libraryID', 'isNot', group.libraryID);
 						}
 						break;