[tldoc] html + \Thanh updates

[Karl Berry]

    H\`an ... Th\`anh displays in all .html translations \'r instead of \`a :(

Looking again ... I don't see it in German or Polish (didn't check the
others).
http://tug.org/texlive/devsrc/Master/texmf-doc/doc/german/texlive-de/texlive-de.html#x1-670009
http://tug.org/texlive/devsrc/Master/texmf-doc/doc/polish/texlive-pl/texlive-pl.html#x1-7500010

Those look like a-grave characters to me.
(~karl/tlm just points to the Master tree, it's nothing special.)

karl