I missed manual page tidy.1 and it is very easy to generate it. Disadvantage is that you need to have libxslt (particularly /usr/bin/xsltproc) installed. Nevertheless, it not needed for the program to run, only for generating the page. Find attached ebuild that installs tidy.1 manual page. Works with the first installation.
Created attachment 86245 [details] HTMLtidy ebuild with man page generation
I realy don't like another dep, not as long as it is just for doc generation. The htmltidy folks should get their act together and supply full processed documentation. I have generated the docs and put it on the mirrors in the -r1 ebuild.