Fix prefixed headings in guide pages meta descriptions

All descriptions and og:description meta tags currently are prefixed with the specific guide's h1. This happens when sanitizing the headers html fragment.

Author: codergeek121

guides/rails_guides/markdown.rb

@@ -23,8 +23,8 @@ def render(body)
       @raw_body = body
       extract_raw_header_and_body
       generate_header
-      generate_description
       generate_title
+      generate_description
       generate_body
       generate_structure
       generate_index
@@ -95,7 +95,7 @@ def generate_header
 
       def generate_description
         sanitizer = Rails::Html::FullSanitizer.new
-        @description = sanitizer.sanitize(@header).squish
+        @description = sanitizer.sanitize(@header).squish.delete_prefix(@heading)
       end
 
       def generate_structure
@@ -167,8 +167,8 @@ def generate_index
       end
 
       def generate_title
-        if heading = html_fragment(@header).at(:h1)
-          @title = "#{heading.text} — Ruby on Rails Guides"
+        if @heading = html_fragment(@header).at(:h1)
+          @title = "#{@heading.text} — Ruby on Rails Guides"
         else
           @title = "Ruby on Rails Guides"
         end