Having these kinds of generated lists alpha-sorted makes it easy to
see what changed in a diff.  Having the SetEnvIf list alphasorted
makes it easy to find which locales are in the list.  Also, this adds
Apache syntax colorization to the documentation.

Here's how I alphasorted the script:

    $ . tools/weblate-supported-langs.sh
    $ echo `for l in $WEBLATE_LANGS; do echo $l; done | sort -u`