Add CHANGELOG for #14886

Also cleanup test a bit

[related #14886]
[related #14743]

actionpack/CHANGELOG.md

+*   Allows ActionDispatch::Request::LOCALHOST to match any IPv4 127.0.0.0/8
+    loopback address.
+
+    *Earl St Sauver*, *Sven Riedel*
+
 *   Preserve original path in `ShowExceptions` middleware by stashing it as
     `env["action_dispatch.original_path"]`
 

actionpack/test/dispatch/request_test.rb

@@ -531,7 +531,7 @@ class RequestCGI < BaseRequestTest
 class LocalhostTest < BaseRequestTest
   test "IPs that match localhost" do
     request = stub_request("REMOTE_IP" => "127.1.1.1", "REMOTE_ADDR" => "127.1.1.1")
-    assert_equal !!request.local?, true 
+    assert request.local?
   end
 end