Fix return types for PHP 8.1

Author: derrabus

OptionsResolver.php

@@ -832,6 +832,7 @@ public function resolve(array $options = [])
      * @throws OptionDefinitionException If there is a cyclic dependency between
      *                                   lazy options and/or normalizers
      */
+    #[\ReturnTypeWillChange]
     public function offsetGet($option/*, bool $triggerDeprecation = true*/)
     {
         if (!$this->locked) {
@@ -1072,6 +1073,7 @@ private function verifyTypes(string $type, $value, array &$invalidTypes, int $le
      *
      * @see \ArrayAccess::offsetExists()
      */
+    #[\ReturnTypeWillChange]
     public function offsetExists($option)
     {
         if (!$this->locked) {
@@ -1088,6 +1090,7 @@ public function offsetExists($option)
      *
      * @throws AccessException
      */
+    #[\ReturnTypeWillChange]
     public function offsetSet($option, $value)
     {
         throw new AccessException('Setting options via array access is not supported. Use setDefault() instead.');
@@ -1100,6 +1103,7 @@ public function offsetSet($option, $value)
      *
      * @throws AccessException
      */
+    #[\ReturnTypeWillChange]
     public function offsetUnset($option)
     {
         throw new AccessException('Removing options via array access is not supported. Use remove() instead.');
@@ -1116,6 +1120,7 @@ public function offsetUnset($option)
      *
      * @see \Countable::count()
      */
+    #[\ReturnTypeWillChange]
     public function count()
     {
         if (!$this->locked) {