MDL-77299 question: Added class properties that are not declared.

In PHP 8.2 and later, setting a value to an undeclared class property is
deprecated and emits a deprecation notice.
So we need to add missing class properties that still need to be declared.

Co-authored-by: Tim Hunt <[email protected]>

question/format.php

@@ -54,6 +54,8 @@ class qformat_default {
     protected $importcontext = null;
     /** @var bool $displayprogress Whether to display progress. */
     public $displayprogress = true;
+    /** @var context[] */
+    public $contexts;
 
     // functions to indicate import/export functionality
     // override to return true if implemented
@@ -166,7 +168,7 @@ class qformat_default {
 
     /**
      * set an array of contexts.
-     * @param array $contexts Moodle course variable
+     * @param context[] $contexts
      */
     public function setContexts($contexts) {
         $this->contexts = $contexts;