Documentation is inconsistent wrt QChronoTimer

https://doc.qt.io/qt-6/timers.html seems to have been updated to QChronoTimer from QTimer without checking for subtle differences between the two classes and probably needs a careful review. Things that I noticed:

• https://doc.qt.io/qt-6/qchronotimer.html has a note that explains why QChronoTimer doesn't have static singleShot() methods - yet https://doc.qt.io/qt-6/timers.html tells that QChronoTimer provides static functions for single-shot timers and gives an example of calling QChronoTimer::singleShot() usage - which won't compile because QChronoTimer actually doesn't have singleShot().
• I'm not sure the paragraph about accuracy is still up-to-date, as it has no word about target systems that have nanosecond-level accuracy. Either QChronoTimer's precision is yet uncalled for (doubtful), or there are systems that can trigger it with higher than 1ms accuracy and these are worth mentioning.