Add labels property to parser

spacy/syntax/nn_parser.pyx

@@ -790,6 +790,11 @@ cdef class Parser:
                 for doc in docs:
                     hook(doc)
 
+    @property
+    def labels(self):
+        class_names = [self.moves.get_class_name(i) for i in range(self.moves.n_moves)]
+        return class_names
+
     @property
     def tok2vec(self):
         '''Return the embedding and convolutional layer of the model.'''