I think they have been excluded from the build for space reasons (they're huge): if you prefer to have it locally, I think you can still download
the sources of the package
Code:
lftp -c mirror http://slackware.osuosl.org/slackware64-14.1/source/l/qt/
remove these three lines from the configure options in qt.SlackBuild
Code:
-nomake examples \
-nomake demos \
-nomake docs \
and rebuild it
Code:
BUILD=3docs ./qt.SlackBuild