rspec/rspec-expectations — pull request #693 by postmodern (2014-12-04 21:59:00+00:00)
Title: Properly sub-class Exception so YARD can detect ExpectationNotMetError.

[rubydoc.org](http://www.rubydoc.info/gems/rspec-expectations/RSpec/Expectations) does not list `ExpectationNotMetError` as a class, but instead a plain constant.