[ci skip] Remove reference to Rails 4 in the initialization guide.

guides/source/documents.yaml

@@ -116,7 +116,7 @@
       name: The Rails Initialization Process
       work_in_progress: true
       url: initialization.html
-      description: This guide explains the internals of the Rails initialization process as of Rails 4.
+      description: This guide explains the internals of the Rails initialization process.
     -
       name: Autoloading and Reloading Constants
       url: autoloading_and_reloading_constants.html

guides/source/initialization.md

@@ -3,8 +3,8 @@
 The Rails Initialization Process
 ================================
 
-This guide explains the internals of the initialization process in Rails
-as of Rails 4. It is an extremely in-depth guide and recommended for advanced Rails developers.
+This guide explains the internals of the initialization process in Rails.
+It is an extremely in-depth guide and recommended for advanced Rails developers.
 
 After reading this guide, you will know: