Document Integer#ordinal available in PR #2072.

Also remove an unasserted line in the tests.

activesupport/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*    Adds Integer#ordinal to get the ordinal suffix string of an integer. *Tim Gildea*
+
 *    AS::Callbacks: `:per_key` option is no longer supported
 
 *    `AS::Callbacks#define_callbacks`: add `:skip_after_callbacks_if_terminated` option.

activesupport/test/core_ext/integer_ext_test.rb

@@ -26,6 +26,5 @@ class IntegerExtTest < ActiveSupport::TestCase
   def test_ordinal
     assert_equal 'st', 1.ordinal
     assert_equal 'th', 8.ordinal
-    1000000000000000000000000000000000000000000000000000000000000000000000.ordinal
   end
 end

railties/guides/source/active_support_core_extensions.textile

@@ -1872,9 +1872,24 @@ The method +multiple_of?+ tests whether an integer is multiple of the argument:
 
 NOTE: Defined in +active_support/core_ext/integer/multiple.rb+.
 
+h4. +ordinal+
+
+The method +ordinal+ returns the ordinal suffix string corresponding to the receiver integer:
+
+<ruby>
+1.ordinal    # => "st"
+2.ordinal    # => "nd"
+53.ordinal   # => "rd"
+2009.ordinal # => "th"
+-21.ordinal  # => "st"
+-134.ordinal # => "th"
+</ruby>
+
+NOTE: Defined in +active_support/core_ext/integer/inflections.rb+.
+
 h4. +ordinalize+
 
-The method +ordinalize+ returns the ordinal string corresponding to the receiver integer:
+The method +ordinalize+ returns the ordinal string corresponding to the receiver integer. In comparison, note that the +ordinal+ method returns *only* the suffix string.
 
 <ruby>
 1.ordinalize    # => "1st"