MBS-10572: update missing docblocks

Author: TobiGa

backup/moodle2/backup_aichat_stepslib.php

@@ -25,6 +25,8 @@
 class backup_aichat_structure_step extends backup_activity_structure_step {
     /**
      * Define structure.
+     *
+     * @return backup_nested_element
      */
     protected function define_structure() {
         $userinfo = $this->get_setting_value('users');

backup/moodle2/restore_aichat_stepslib.php

@@ -27,6 +27,8 @@
 class restore_aichat_structure_step extends restore_activity_structure_step {
     /**
      * Define structure.
+     *
+     * @return array
      */
     protected function define_structure() {
         $paths = [];

db/upgrade.php

@@ -27,6 +27,7 @@
  * Define upgrade steps to be performed to upgrade the plugin from the old version to the current one.
  *
  * @param int $oldversion Version number the plugin is being upgraded from.
+ * @return bool
  */
 function xmldb_aichat_upgrade($oldversion) {
     global $DB;

index.php

@@ -15,7 +15,7 @@
 // along with Moodle.  If not, see <https://www.gnu.org/licenses/>.
 
 /**
- * View a aichat instance
+ * View an aichat instance
  *
  * @package     mod_aichat
  * @copyright   2025 ISB Bayern