rename some variables for clarity

src/externalldap.js

@@ -443,7 +443,7 @@ async function syncGroups(config, progressCallback) {
             if (error) debug('syncGroups: Failed to create group', groupName, error);
         } else {
             // convert local group to ldap group. 2 reasons:
-            // 1. we reset source flag when externalldap is disabled. if we renable, it automatically coverts
+            // 1. we reset source flag when externalldap is disabled. if we renable, it automatically converts
             // 2. externalldap connector usually implies user wants to user external users/groups.
             groups.update(result.id, { source: 'ldap' });
             debug(`syncGroups: [up-to-date group] groupname=${groupName}`);