FTBFS Assistant: qlitehtml: ‘int DocumentContainerPrivate::pt_to_px(int) const’ marked ‘override’, but does not override

In file included from /home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/container_qpainter.cpp:5:
/home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/container_qpainter_p.h:74:9: error: ‘int DocumentContainerPrivate::pt_to_px(int) const’ marked ‘override’, but does not override
   74 |     int pt_to_px(int pt) const override;
      |         ^~~~~~~~
/home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/container_qpainter.cpp: In constructor ‘DocumentContainer::DocumentContainer()’:
/home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/container_qpainter.cpp:436:13: error: invalid new-expression of abstract class type ‘DocumentContainerPrivate’
  436 |     : d(new DocumentContainerPrivate)
      |             ^~~~~~~~~~~~~~~~~~~~~~~~
/home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/container_qpainter_p.h:58:7: note:   because the following virtual functions are pure within ‘DocumentContainerPrivate’:
   58 | class DocumentContainerPrivate final : public litehtml::document_container
      |       ^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/3rdparty/litehtml/include/litehtml.h:4,
                 from /home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/container_qpainter_p.h:8:
/home/tjmaciei/src/qt/qt6-release/qttools/src/assistant/qlitehtml/src/3rdparty/litehtml/include/litehtml/html.h:41:65: note:     ‘virtual int litehtml::document_container::pt_to_px(int)’
   41 |                 virtual int                                     pt_to_px(int pt) = 0;
      |                                                                 ^~~~~~~~