Fill out API Documentation Guidelines 'you will learn' list.

guides/source/api_documentation_guidelines.md

@@ -5,6 +5,10 @@ This guide documents the Ruby on Rails API documentation guidelines.
 
 After reading this guide, you will know:
 
+* What RDoc is.
+* How to write effective prose for documentation purposes.
+* Style guidlines for documenting different kinds of Ruby code.
+
 --------------------------------------------------------------------------------
 
 RDoc