Add DSL description to documentation.

- contains features still to be implemented
3 jobs for 33-make-specification-langauge-more-concise in 8 minutes and 37 seconds (queued for 5 seconds)
Status Name Job ID Coverage
  Build
passed build #27041

00:00:39

 
  Test
passed test #27042

00:07:58

 
  Ragdoc Build
passed ragdoc_build #27043

00:00:16