QDoc doesn't list the HTML as part of the example.
There are a few Web* modules that do have examples that have HTML files as part of the example.

Also, CSS files and possibly any file should be listed in the generated example list.

Examples:
1)http://qt-project.org/doc/qt-5/qtwebkitexamples-webkitwidgets-imageanalyzer-example.html

2)Standalone example (Qt WebChannel)

They have files called index.html which is part of the example. The QRC files list them as well as any images or CSS files.