Improve the commentary front matter

Author: bbatsov

parseedn.el

@@ -26,7 +26,16 @@
 
 ;;; Commentary:
 
-;; The EDN <-> Elisp reader and printer
+;; parseedn is an Emacs Lisp library for parsing EDN (Clojure) data.
+;; It uses parseclj's shift-reduce parser internally.
+
+;; EDN and Emacs Lisp have some important differences that make
+;; translation from one to the other not transparent (think
+;; representing an EDN map into Elisp, or being able to differentiate
+;; between false and nil in Elisp). Because of this, parseedn takes
+;; certain decisions when parsing and transforming EDN data into Elisp
+;; data types.  For more information please refer to parseclj's design
+;; documentation.
 
 ;;; Code: