Fixes for modules/cron

modules/cron/hooks/hook_configpage.php

 <?php
+
 /**
  * Hook to add the cron module to the config page.
  *
  * @param \SimpleSAML\XHTML\Template &$template The template that we should alter in this hook.
+ * @return void
  */
-
 function cron_hook_configpage(\SimpleSAML\XHTML\Template &$template)
 {
     $template->data['links']['cron'] = [

modules/cron/hooks/hook_cron.php

 <?php
+
 /**
  * Hook to run a cron job.
  *
  * @param array &$croninfo  Output
+ * @return void
  */
-
 function cron_hook_cron(&$croninfo)
 {
     assert(is_array($croninfo));

modules/cron/hooks/hook_frontpage.php

 <?php
+
 /**
  * Hook to add the modinfo module to the frontpage.
  *
  * @param array &$links  The links on the frontpage, split into sections.
+ * @return void
  */
-
 function cron_hook_frontpage(&$links)
 {
     assert(is_array($links));

modules/cron/lib/Cron.php

 <?php
 
-namespace  SimpleSAML\Module\cron;
+namespace SimpleSAML\Module\cron;
 
 /**
  * Handles interactions with SSP's cron system/hooks.
@@ -27,13 +27,12 @@ class Cron
 
     /**
      * Invoke the cron hook for the given tag
-     * @param $tag string The tag to use. Must be valid in the cronConfig
+     * @param string $tag The tag to use. Must be valid in the cronConfig
      * @return array the tag, and summary information from the run.
      * @throws Exception If an invalid tag specified
      */
     public function runTag($tag)
     {
-
         if (!$this->isValidTag($tag)) {
             throw new \Exception("Invalid cron tag '$tag''");
         }
@@ -53,6 +52,10 @@ class Cron
         return $croninfo;
     }
 
+    /**
+     * @param string $tag
+     * @return bool
+     */
     public function isValidTag($tag)
     {
         if (!is_null($this->cronconfig->getValue('allowed_tags'))) {