Issue #3079444 by jdmoreno: ExtensionList::reset() doesn't document its return value

core/lib/Drupal/Core/Extension/ExtensionList.php

@@ -157,6 +157,8 @@ protected function getExtensionDiscovery() {
    * We don't reset statically added filenames, as it is a static cache which
    * logically can't change. This is done for performance reasons of the
    * installer.
+   *
+   * @return $this
    */
   public function reset() {
     $this->extensions = NULL;