[tldoc] doc updates this week

[Karl Berry]

Hi everyone - a reminder that I'm planning to close down TL updates and
build the final images at the end of this coming week (Fri Mar 27).

So it would be great to get any and all TL Guide and any other
translation updates in asap; many thanks to those who have already done
it. The ones that remain look to be:
  cz de it ru sr zh-cn

Also, for the small update to the top-level readme
(readme-html.dir/readme.en.html and readme-txt.dir/README.EN), the
remaining list looks like:
  cs de it pt-br sr vi zh-cn

I'm not sure if the people who created the original translations for
those in addition to the TL Guide translations, namely Portuguese BR,
Serbian, and Vietnamese, are still here. If so, please chime in. If not,
can anyone here take a stab at them?

I realize the world is in flux. If the translation updates don't get
made, clearly it's not critical. It can always happen later. Just wanted
to send out a note. --thanks, karl.