Add test_em_dash() to WrapTestCase to make sure that TextWrapper handles em-dashes -- like this -- properly.  (Also--like this.  Although this usage may be incompatible with fixing bug #596434; we shall see.)
Add test_em_dash() to WrapTestCase to make sure that TextWrapper handles
em-dashes -- like this -- properly.  (Also--like this.  Although this
usage may be incompatible with fixing bug #596434; we shall see.)

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator