Recover Doc objects from the annotations, using the given vocab.

def get_docs(self, vocab):
        """Recover Doc objects from the annotations, using the given vocab."""
        for string in self.strings:
            vocab[string]
        orth_col = self.attrs.index(ORTH)
        for tokens, spaces in zip(self.tokens, self.spaces):
            words = [vocab.strings[orth] for orth in tokens[:, orth_col]]
            doc = Doc(vocab, words=words, spaces=spaces)
            doc = doc.from_array(self.attrs, tokens)
            yield doc