[tldoc] Slovak translation of sk.po

[Karl Berry]

    Left pane: Serbian-specific letters (œô¨¨, œô¨«, œô¨©) are not sorted correctly.

What Norbert did (at my suggestion, don't blame him :) was simply to use
Perl sort/cmp on the translated strings (instead of the English
strings).

We are well aware that the collation order will therefore be incorrect.
I assume that is what is happening here.  Hopefully it is still at least
somewhat better than sorting the English.  If there's a consensus it's
better to sort according to English and display the Serbian (or
whatever), as we were doing before, we can revert the change.

Getting the sorting actually correct means finding and loading
complicated/extra packages, and we are (I am) not willing to entertain
that, at least not for this year.

k