third test to warn against reading guides in GitHub

guides/rails_guides/markdown/renderer.rb

@@ -25,7 +25,7 @@ HTML
       def paragraph(text)
         if text =~ /^(TIP|IMPORTANT|CAUTION|WARNING|NOTE|INFO|TODO)[.:](.*?)/
           convert_notes(text)
-        elsif text.include?('DO NOT READ THIS FILE')
+        elsif text.include?('DO NOT READ THIS FILE IN GITHUB')
         elsif text =~ /^\[<sup>(\d+)\]:<\/sup> (.+)$/
           linkback = %(<a href="#footnote-#{$1}-ref"><sup>#{$1}</sup></a>)
           %(<p class="footnote" id="footnote-#{$1}">#{linkback} #{$2}</p>)

guides/source/2_2_release_notes.md

@@ -1,4 +1,4 @@
-**DO NOT READ THIS FILE, guides are published in http://guides.rubyonrails.org.**
+**DO NOT READ THIS FILE IN GITHUB, GUIDES ARE PUBLISHED IN http://guides.rubyonrails.org.**
 
 Ruby on Rails 2.2 Release Notes
 ===============================