[PyQt] Docs have incorrect link to C++ classes

[David Cortesi]

The Class reference at
http://pyqt.sourceforge.net/Docs/PyQt5/index.html
has for many (all?) classes a link to "C++ documentation"
and all of these return 404 pages from qt-project.org.

Incorrect link from QAbstractTableModel:
   http://qt-project.org/doc/qt-5/qtcore/qabstracttablemodel.html
Correct link:
  http://qt-project.org/doc/qt-5/qabstracttablemodel.html

It appears the pyqt pages insert a group ("/api/", "/qtcore/")
in the URL where the qt-project structure is just
a flat list of class names with no grouping.