programatically adding comments to domain/problem

[lettuce-program]

As a developer looking at programmatic generation of problems and domains, I want to be able to generate comments for the domain so there is human-readable context, e.g., a complex action can have a natural language description (in a comment) that prefaces it.

• top level comment for domains
• comments for actions

The domain should look like:

;; This domain does x, y.
(define (domain test) 
  ..omitted..
  
  ;; This action updates predicate a when b is at c
  (:action test
  ..omitted..
  )
)