Fix broken document for `upsertWithWhere`

lib/persisted-model.js

@@ -123,7 +123,7 @@ module.exports = function(registry) {
    * If there is a single instance retrieved, update the retrieved model.
    * Creates a new model if no model instances were found.
    * Returns an error if multiple instances are found.
-   * * @param {Object} [where]  `where` filter, like
+   * @param {Object} [where]  `where` filter, like
    * ```
    * { key: val, key2: {gt: 'val2'}, ...}
    * ```