Fix doc typo. Move extend self so it's more immediately obvious. Requ…

…ire inflections from load path.

activesupport/lib/active_support/inflector.rb

@@ -10,6 +10,8 @@ module ActiveSupport
   # If you discover an incorrect inflection and require it for your application, you'll need
   # to correct it yourself (explained below).
   module Inflector
+    extend self
+
     # A singleton instance of this class is yielded by Inflector.inflections, which can then be used to specify additional
     # inflection rules. Examples:
     #
@@ -91,8 +93,6 @@ def clear(scope = :all)
       end
     end
 
-    extend self
-
     # Yields a singleton instance of Inflector::Inflections so you can specify additional
     # inflector rules.
     #
@@ -134,7 +134,7 @@ def pluralize(word)
     #   "posts".singularize            # => "post"
     #   "octopi".singularize           # => "octopus"
     #   "sheep".singluarize            # => "sheep"
-    #   "word".singluarize             # => "word"
+    #   "word".singularize             # => "word"
     #   "the blue mailmen".singularize # => "the blue mailman"
     #   "CamelOctopi".singularize      # => "CamelOctopus"
     def singularize(word)
@@ -307,4 +307,4 @@ def ordinalize(number)
   end
 end
 
-require File.dirname(__FILE__) + '/inflections'
+require 'active_support/inflections'