Add documentation facility

[KeenS]

WIP

• discuss document format
• document standard procs (I prepared some skeltons)
• Ability to document other than procs

I know now benz support attributes for all type of objects, but I don't know how to reference them (e.g. marcos, libraries).

[nyuichi]

@KeenS

I love it :heart:

I don't know how to reference them (e.g. marcos, libraries).

On macros, why don't you make a syntax overriding normal define-syntax like following?

(define-syntax foo
  "this is a document for foo"
  ...)

[KeenS]

@wasabiz Oh I've forgotten define-syntax and define-library. I'll custom them too. However, when you consider to document existing macros, you finally need reference macro objects. As libraries in picrin are reopenable, you can document libraries.