doc: fix: docstring: use Promise

frontend/static/js/api/account.js

@@ -16,7 +16,7 @@ class Account
 	/**
 	 * @param {String} username 
 	 * @param {String} password 
-	 * @returns 
+	 * @returns {?Promise<Object>}
 	 */
 	async create(username, password)
 	{
@@ -33,7 +33,7 @@ class Account
 
 	/**
 	 * @param {String} password 
-	 * @returns 
+	 * @returns {?Promise<Object>}
 	 */
 	async delete(password)
 	{
@@ -52,7 +52,7 @@ class Account
 
 	/**
 	 * Get account data (username)
-	 * @returns 
+	 * @returns {?Promise<Object>}
 	 */
 	async get()
 	{
@@ -71,7 +71,7 @@ class Account
 	 * 
 	 * @param {*} data 
 	 * @param {Number} password 
-	 * @returns 
+	 * @returns {?Object}
 	 */
 	async update(data, password)
 	{