Please, add 40ants-doc library

[svetlyak40wt]

It is based on MGL-PAX and provides a way to keep documentation along with code. Every documented object can cross-reference others.

Why this fork is different from MGL-PAX

• Core system 40ANTS-DOC now has only two dependencies on NAMED-READTABLES and PYTHONIC-STRING-READER. If you want to compile documentation, load 40ANTS-DOC/FULL system which will download such dependencies as markdown parser and more.

• Now you don't have to import any locative symbols into your package. Import only a DEFSECTION macro and it will be enough to define documentation for your library!

• Added a warning mechanism, which will issue such warnings on words that looks like a symbol, but when real symbol or reference is absent:

  WARNING: Unable to find symbol "API" mentioned in (CL-INFO:@INDEX SECTION)
  

I'm planning to extend this fork even more.

The source is here: https://github.com/40ants/doc