QDoc: Fix swapped node maps for annotated lists in DocBook output

In DocBookGenerator, \generatelist annotatedexamples was fed the
attributions map and \generatelist annotatedattributions the examples
map. As both maps are typically empty in the other's documentation
project, both commands silently generated an empty list.

Swap the two to match HtmlGenerator.

This also makes the `attributions` test project cover the DocBook
output of annotated attribution lists, including the duplicate
removal added in the previous commit; update the expected data
accordingly.

Pick-to: 6.12
Change-Id: I05b795815183d7f3b8d45d8ca09a9de64f6d6988
Reviewed-by: Paul Wicking <paul.wicking@qt.io>