[tldoc] html + \Thanh updates

[Karl Berry]

    In German I still see racute instead of agrave, sorry.

Browser problems, kill/restart?  Interpretation in a different (Latin 2)
character set?  It's unfathomable to me that you see \'r and I see \`a.
But I do.  Really.  The output is using   and the document
declares itself iso-8859-1, so ...

Maybe that iso-8859-1 (which comes from live4ht.cfg) is the problem.  I
see it appears in texlive-pl.html too, but I bet it should really be
iso-8859-2.

    Just corrected and commited. I use more simply way with live4ht.cfg OK?

I don't understand.  I don't see any changes to live4ht.cfg.  Anyway,
if whatever you did works better for you, good :).

karl