Issue #1808632 by kiamlaluno: Fix example in docs for config() function

core/includes/config.inc

@@ -52,12 +52,12 @@ function config_get_storage_names_with_prefix($prefix = '') {
  * Retrieves a configuration object.
  *
  * This is the main entry point to the configuration API. Calling
- * @code config(book.admin) @endcode will return a configuration object in which
- * the book module can store its administrative settings.
+ * @code config('book.admin') @endcode will return a configuration object in
+ * which the book module can store its administrative settings.
  *
  * @param $name
  *   The name of the configuration object to retrieve. The name corresponds to
- *   a configuration file. For @code config(book.admin) @endcode, the config
+ *   a configuration file. For @code config('book.admin') @endcode, the config
  *   object returned will contain the contents of book.admin configuration file.
  *
  * @return Drupal\Core\Config\Config