Fix typo in error reporting.  This doesn't need to go into the release branch (if it ever gets to the typo, the test is failing anyway).
Fix typo in error reporting.  This doesn't need to go into the release
branch (if it ever gets to the typo, the test is failing anyway).

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