fix Docs [ci skip]

actionview/lib/action_view/helpers/sanitize_helper.rb

@@ -120,7 +120,7 @@ module ClassMethods #:nodoc:
         attr_writer :full_sanitizer, :link_sanitizer, :white_list_sanitizer
 
         # Vendors the full, link and white list sanitizers.
-        # Provided strictly for compabitility and can be removed in Rails 5.
+        # Provided strictly for compatibility and can be removed in Rails 5.
         def sanitizer_vendor
           Rails::Html::Sanitizer
         end