Update lib/schema.js

Co-authored-by: hasezoey <hasezoey@gmail.com>

Author: vkarpov15

lib/schema.js

@@ -919,6 +919,9 @@ Schema.prototype.clearIndexes = function clearIndexes() {
  *     const ToySchema = new Schema({ name: String, color: String, price: Number });
  *     ToySchema.searchIndex({ name: 'test', definition: { mappings: { dynamic: true } } });
  *
+ * @param {Object} description index options, including `name` and `definition`
+ * @param {String} description.name
+ * @param {Object} description.definition
  * @return {Schema} the Schema instance
  * @api public
  */