Improve latest AR and AP changelog entries

actionpack/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
-*   Add `separation` option for `ActionView::Helpers::TextHelper.excerpt`. *Guirec Corbel*
+*   Add `separator` option for `ActionView::Helpers::TextHelper#excerpt`:
+
+        excerpt('This is a very beautiful morning', 'very', :separator  => ' ', :radius => 1)
+        # => ...a very beautiful...
+
+    *Guirec Corbel*
 
 *   Added controller-level etag additions that will be part of the action etag computation *Jeremy Kemper/DHH*
 

activerecord/CHANGELOG.md

 ## Rails 4.0.0 (unreleased) ##
 
-*   `ActiveRecord::SchemaDumper` use the Ruby 1.9 style hash. *Konstantin Shabanov*
+*   `ActiveRecord::SchemaDumper` uses Ruby 1.9 style hash, which means that the
+    schema.rb file will be generated using this new syntax from now on.
+
+    *Konstantin Shabanov*
 
 *   Map interval with precision to string datatype in PostgreSQL. Fixes #7518. *Yves Senn*