fix deprecation warnings

We were getting these warnings with Qt-6.X, with X>5:

compiling moc/moc_helgrind_object.cpp
In file included from /usr/include/qt6/QtCore/qtconfigmacros.h:12,
                 from /usr/include/qt6/QtCore/qtcoreglobal.h:13,
                 from /usr/include/qt6/QtCore/qglobal.h:24,
                 from /usr/include/qt6/QtGui/qtguiglobal.h:7,
                 from /usr/include/qt6/QtWidgets/qtwidgetsglobal.h:8,
                 from /usr/include/qt6/QtWidgets/qcombobox.h:8,
                 from /usr/include/qt6/QtWidgets/QComboBox:1,
                 from ./help/help_handbook.h:24,
                 from moc/../help/help_about.h:24,
                 from moc/moc_help_about.cpp:9:
/usr/include/qt6/QtCore/qtdeprecationdefinitions.h:18:4: warning: #warning QT_DISABLE_DEPRECATED_UP_TO is set to the version that is lower than the version that Qt was built with. This may lead to linking issues
. [-Wcpp]
   18 | #  warning QT_DISABLE_DEPRECATED_UP_TO is set to the version that is lower than the version that \
      |    ^~~~~~~

Signed-off-by: Moritz Barsnick <barsnick@gmx.net>

Author: barsnick

vk_config.pri

@@ -35,7 +35,6 @@ QT += widgets
 greaterThan(QT_MAJOR_VERSION, 5) {
     QT += core5compat
 }
-DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x000000
 
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 # Project configuration & compiler options