New functionality for QAbstractProxyModel::buddy() not documented

In Qt 4.7.x classes derived from QAbstractProxyModel used the default implementation for buddy() (i.e. QAbstractItemModel::buddy()). In Qt 4.8.x, a new override of this function was added to QAbstractProxyModel. This new function is documented in the Qt Assistant with the substantially less-than-helpful:

Reimplemented from QAbstractItemModel::buddy().

This function was introduced in Qt 4.8.

As this function's operation is different from that of 4.7, this documentation is useless when (for example) one is trying to track down the source of previously working code breaking when Qt is updated from 4.7 to 4.8

The documentation for this function (and, for that matter, for several other new overrides in this specific class) need to be updated to detail what this functin does differently than the base class implementation.