make sure the inflection rules are loaded when cherry-picking...

make sure the inflection rules are loaded when cherry-picking active_support/core_ext/string/inflections.rb [fixes #6884]

activesupport/lib/active_support/inflections.rb

+require 'active_support/inflector/inflections'
+
 module ActiveSupport
   Inflector.inflections do |inflect|
     inflect.plural(/$/, 's')

activesupport/lib/active_support/inflector/inflections.rb

@@ -2,6 +2,8 @@
 
 module ActiveSupport
   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.
     #

activesupport/lib/active_support/inflector/methods.rb

 # encoding: utf-8
 
 require 'active_support/inflector/inflections'
+require 'active_support/inflections'
 
 module ActiveSupport
   # The Inflector transforms words from singular to plural, class names to table names, modularized class names to ones without,