[texdoc] texdoc babel-german

[Karl Berry]

Hi Denis,

    Strange: on my TL 2017, `texdoc -l hyph-utf8' returns:

Not so strange. The difference, as Takuto surmised, is because I was
using the development hierarchy which has the latest Catalogue changes.

And I had changed the Catalogue to have a description for
hyphenation.pdf precisely as a result of the report.

And the next hyph-utf8 release will name the doc file hyph-utf8.pdf,
also as a result of this report :). --best, karl.