clarified spec

--HG--
extra : convert_revision : svn%3Afdd8eb12-d10e-0410-9acb-85c331704f74/trunk%404069

dlib/svm/one_vs_one_trainer_abstract.h

@@ -80,7 +80,7 @@ namespace dlib
             requires
                 - l1 != l2
             ensures
-                - Sets the trainer object used to create binary classifiers to
+                - Sets the trainer object used to create a binary classifier to
                   distinguish l1 labeled samples from l2 labeled samples.
         !*/