[tldistro] Texdoc installation

[Takuto ASAKURA]

Dear All,

this is Takuto Asakura, a maintainer of Texdoc. I'd like to announce a
little change in the new version of Texdoc, which we released last June.

In short, from Texdoc v3.0, we won't in­clude Data.tlpdb.lua (the pseudo
cache file) in our repos­i­tory. If your dis­tri­bu­tion do not ship the tlpdb,
you need to pre-gen­er­ate the pseudo cache file to make Tex­doc work­able.

Detailed procedure:

1. Run texdoc command with an argument (e.g., `texdoc -lM texlive-en`)
   under a TeX Live setup *with tlpdb* to generate a flesh cache file.
2. Copy the cache file (expected to be $TEXMFVAR/texdoc/cache-tlpdb.lua)
   to the same directory with the Texdoc's scripts as Data.tlpdb.lua.
   Please be aware of the file name.

I'm sorry for your inconvenience but thank you for your cooperation.

Best regards,
Takuto