Update lib/options/schemaUnionOptions.js

Co-authored-by: Copilot <[email protected]>

Author: vkarpov15

lib/options/schemaUnionOptions.js

@@ -15,15 +15,15 @@ class SchemaUnionOptions extends SchemaTypeOptions {}
 const opts = require('./propertyOptions');
 
 /**
- * If set, specifies the type of this map's values. Mongoose will cast
- * this map's values to the given type.
+ * If set, specifies the types that this union can take. Mongoose will cast
+ * the value to one of the given types.
  *
- * If not set, Mongoose will not cast the map's values.
+ * If not set, Mongoose will not cast the value to any specific type.
  *
  * @api public
  * @property of
  * @memberOf SchemaUnionOptions
- * @type {Function|string}
+ * @type {Function|Function[]|string|string[]}
  * @instance
  */