qt.cfg: Activated commented out configuration, since #8479 was fixed (#6150)

Reference: https://trac.cppcheck.net/ticket/8479

Author: orbitcowboy

cfg/qt.cfg

@@ -5254,9 +5254,7 @@
   <!-- Treat QStringList as QList<QString> since we can't remove the template parameter when we inherit. -->
   <define name="QStringList" value="QList&lt;QString&gt;"/>
   <define name="Q_ARG(type, data)" value="QArgument&lt;type &gt;(#type, data)"/>
-  <!-- TODO: Enable when ticket 8479 got fixed
   <define name="Q_D(Class)" value="Class##Private * const d = d_func()"/>
-  -->
   <define name="Q_CLASSINFO(Name, Value)" value=""/>
   <define name="Q_EXPORT_PLUGIN(ClassName)" value=""/>
   <define name="Q_EXPORT_PLUGIN2(a,ClassName)" value=""/>