[ci skip] Remove duplicated transaction arg in truncate, closes #6893

lib/model.js

@@ -2304,7 +2304,6 @@ class Model {
    * Truncate all instances of the model. This is a convenient method for Model.destroy({ truncate: true }).
    *
    * @param {object} [options] The options passed to Model.destroy in addition to truncate
-   * @param {Boolean|function} [options.transaction] Transaction to run query under
    * @param {Boolean|function} [options.cascade = false] Only used in conjunction with TRUNCATE. Truncates  all tables that have foreign-key references to the named table, or to any tables added to the group due to CASCADE.
    * @param {Transaction}      [options.transaction] Transaction to run query under
    * @param {Boolean|function} [options.logging] A function that logs sql queries, or false for no logging