Ignore \deprecated [x.y] if x.y is a future version

When \deprecate is used for future Qt version, qdoc should ignore the deprecation command.

Example: https://doc-snapshots.qt.io/qt6-dev/qcheckbox-obsolete.html#stateChanged

Despite what the documentation says, this method is not deprecated just yet (in Qt 6.7, Qt 6.8). It will be in Qt 6.9, though:

/*!
    \fn void QCheckBox::stateChanged(int state)

    \deprecated [6.9] Use checkStateChanged(Qt::CheckState) instead.
*/

In this case, it would be arguably better that Qdoc compares the version in the brackets to the current Qt version, and ignores the command for Qt 6.7, 6.8.