Verify document build error and warning status

Run a qdoc document build for QSR:

qtsaferenderer/qmake

qtsaferenderer/make html_docs

--> expected result: no documentation warnings or errors.

Currently there are quite many warnings (see the attachment) on the build but on the other hand, the API documentation update is ongoing. However, before releasing QSR 1.1, it must be verified that there are no documentation errors/warnings in the build.