activeqt-container.html: one anchor for two sections

In https://doc.qt.io/qt-6/activeqt-container.html, the link https://doc.qt.io/qt-6/activeqt-container.html#typical-error-messages corresponds to the two sections "Typical Error Messages", one under "Instantiating COM Objects", the other under "Accessing the Object API".

Both anchors should be different. (I'm not sure how this is possible with the current QDoc code, as both anchors are generated with \section2.)

This issue is slightly related to QTBUG-122261, as it's also about anchors, but I'm quite sure the solution will need to be different.