add changelog & docs for Pry.main

CHANGELOG.md

@@ -27,6 +27,7 @@
 * lazy load `Pry::InputCompleter` or `Pry::BondCompleter`.
   - `Pry::BondCompleter` is loaded when the "bond" gem is available and editline is not being used(OSX)
 * add option to disable input completer through `_pry_.config.completer = nil`
+* add `Pry.main`. returns a special instance of Object referenced by self of `TOPLEVEL_BINDING`: "main".
 * add `Pry::LastException` (#1145)
 
 #### Bug fixes, etc.

lib/pry/pry_class.rb

@@ -34,6 +34,10 @@ class Pry
     end
   end
 
+  #
+  # @return [main]
+  #   returns the special instance of Object, "main".
+  #
   def self.main
     @main ||= TOPLEVEL_BINDING.eval "self"
   end