make build reproducible by fixing sort order in docs

From Debian https://bugs.debian.org/835463
 Description: Make the build reproducible
 Author: Chris Lamb <lamby@debian.org>
 Last-Update: 2016-08-26
1 job for fix-push-requests in 19 minutes and 23 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #3465580
test

00:19:23