`texdoc` search algorithm and language settings

[Werner LEMBERG]

> I suggest that texdoc uses the standard POSIX mechanism for that:
>
> ```
> LANGUAGE=sk:en:ru:hi:da:nb:nn:sv
> ```

I have to correct myself.  The `LANGUAGE` environment variable is not
POSIX but the standard behaviour of GNU gettext; see

  https://www.gnu.org/software/gettext/manual/html_node/Locale-Environment-Variables.html
  https://www.gnu.org/software/gettext/manual/html_node/The-LANGUAGE-variable.html

Not sure whether it is possible to build texdoc on all platforms with
gettext...


    Werner