[tldoc] translation updates for 2023

[Karl Berry]

Sorry I failed to send out many reminders, but some of the translations
of the TeX Live manual haven't been updated this year (or, in some
cases, for a year or two before that). Namely:

texlive-cz -- Jan/Petr?
texlive-it -- Marco?
texlive-ru -- Vladimir/Boris?
texlive-sr -- Nikola?

The English sources, as usual, are in
https://tug.org/svn/texlive/trunk/Master/texmf-dist/doc/texlive/texlive-en/

(Or the texlive-en package in the TL pretest.)

As for the po files, they look to be basically ok except for zh_CN, but
I'll append a list sorted by translations needed. You can get any .po
file from
https://tug.org/svn/texlive/trunk/Master/tlpkg/translations/
For example,
https://tug.org/svn/texlive/trunk/Master/tlpkg/translations/es.po?view=co
for Spanish.

It will be no problem to commit updates after the release, and most
users will get them, so please go ahead with updates if you have time
and interest. If you'd rather step down from translating, please let me
know so I can update https://tug.org/texlive/doc.html.  --thanks, karl.

--------
zh_CN.po 121 translated messages, 5 fuzzy translations, 273 untranslated messages.
   uk.po 354 translated messages, 45 untranslated messages.
   es.po 356 translated messages, 43 untranslated messages.
   sr.po 373 translated messages, 26 untranslated messages.
   vi.po 387 translated messages, 12 untranslated messages.
   it.po 388 translated messages, 11 untranslated messages.
   da.po 389 translated messages, 10 untranslated messages.
pt_BR.po 393 translated messages, 6 untranslated messages.
   pl.po 397 translated messages, 2 untranslated messages.
   sl.po 310 translated messages, 88 fuzzy translations, 1 untranslated message.
zh_TW.po 398 translated messages, 1 untranslated message.
   sk.po 398 translated messages, 1 untranslated message.
   ru.po 398 translated messages, 1 untranslated message.
   de.po 398 translated messages, 1 untranslated message.
   cs.po 398 translated messages, 1 untranslated message.
   nl.po 399 translated messages.
   ja.po 399 translated messages.
   fr.po 399 translated messages.