* Define HTMLPurifier_Lexer::$_entity_parser property
This fixes a PHP 8.2 deprecation.
* Define HTMLPurifier_URIFilterHarness::$filter property
This fixes a PHP 8.2 deprecation.
* Define HTMLPurifier_AttrTransform_NameSync::$idDef property
This fixes a PHP 8.2 deprecation.
* Define HTMLPurifier_AttrTransform_NameSyncTest::$accumulator property
This fixes a PHP 8.2 deprecation.
* Define HTMLPurifier_AttrValidator_ErrorsTest::$language property
This fixes a PHP 8.2 deprecation.
* Define HTMLPurifier_ChildDef_List::$whitespace property
This fixes a PHP 8.2 deprecation.
* Do not modify incoming tokens in RemoveSpansWithoutAttributes
Previously the undefined property `->markForDeletion` was added to the incoming
tokens. This causes a deprecation in PHP 8.2. Fix this by storing to-be-deleted
tokens inside SplObjectStorage. In PHP 8 a WeakMap would be preferable, as that
prevents leaks if `handleEnd` is never called for the token.
