Update QDoc and qtattributionsscanner to the latest versions from
qttools/dev.
The QDoc binary is built against libClang v18.1.7. It supports new
commands introduced in Qt 6.7 and 6.8. It also ignores duplicate
warnings that QDoc issues for certain attribution files in CI only,
which have been known to block qt5.git integrations previously.
Fixes: QTBUG-126407
Pick-to: 6.8
Change-Id: I69aad04bbe73e1fdf1d6cb4ff797616a23abcdaf
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>
957b74a7fa