guides: adds page title to home and credits, and revises it in the rest

railties/guides/rails_guides/generator.rb

@@ -148,7 +148,7 @@ def set_header_section(body, view)
       header = $1
 
       header =~ /h2\.(.*)/
-      page_title = $1.strip
+      page_title = "Ruby on Rails Guides: #{$1.strip}"
 
       header = textile(header)
 

railties/guides/source/credits.html.erb

+<% content_for :page_title do %>
+Ruby on Rails Guides: Credits
+<% end %>
+
 <% content_for :header_section do %>
 <h2>Credits</h2>
 

railties/guides/source/index.html.erb

+<% content_for :page_title do %>
+Ruby on Rails Guides
+<% end %>
+
 <% content_for :header_section do %>
 <h2>Ruby on Rails Guides</h2>