TreeView: TreeView.modelIndex() has the order of row and column swapped

In Qt 6.3, TreeView had a function called modelIndex().
This function took two arguments: row and column.
In Qt 6.4, This function was moved into TableView
(the superclass) instead, since it was both places.
And in that process (probably because this was done
in several patches), the order of the arguments got
swapped, to conform with two other functions in
TableView that took a column and row as argument.

But this was a source incompatible change.

The result is that TreeView in Qt 6.3 has a function
modelIndex(row, column) that works differently compared
to Qt 6.4.0. There the signature is modelIndex(column, row).