Fix typo in [8287]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@8294 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

actionpack/lib/action_view/helpers/scriptaculous_helper.rb

@@ -77,7 +77,7 @@ def visual_effect(name, element_id = false, js_options = {})
       # attributes in the form "string_identifier". For example, "item_1". Only
       # the identifier part of the id attribute will be serialized.
       # 
-      # Addtional +options+ are:
+      # Additional +options+ are:
       #
       # <tt>:format</tt>::               A regular expression to determine what to send
       #                                  as the serialized id to the server (the default