Fix nullable properties validation

Author: sergeynezbritskiy

Magento2/Sniffs/Commenting/ClassPropertyPHPDocFormattingSniff.php

@@ -28,7 +28,8 @@ class ClassPropertyPHPDocFormattingSniff extends AbstractVariableSniff
         T_WHITESPACE,
         T_NS_SEPARATOR,
         T_STRING,
-        T_COMMENT
+        T_COMMENT,
+        T_NULLABLE
     ];
 
     /**

Magento2/Tests/Commenting/ClassPropertyPHPDocFormattingUnitTest.inc

@@ -135,4 +135,11 @@ class correctlyFormattedClassMemberDocBlock
      * @var string
      */
     protected string $test1;
+
+    /**
+     * Ensure that nullable sign in the property type hint declaration is interpreted correctly
+     *
+     * @var string|null
+     */
+    protected ?string $test2;
 }