Changelog for #1990

[skip ci]

Author: JonRowe

Changelog.md

@@ -66,6 +66,8 @@ Bug Fixes:
   prepended or extended by config defined after an example group. (Eugene Kenny, #1935)
 * Fix regression which caused shared examples to be mistakenly run when specs
   where filtered to a particular location.  (Ben Axnick, #1963)
+* Fix regression where the formatter loader would allow duplicate formatters.
+  (Jon Rowe, #1990)
 
 ### 3.2.3 / 2015-04-06
 [Full Changelog](http://github.com/rspec/rspec-core/compare/v3.2.2...v3.2.3)