Improved comments.

Co-authored-by: Radim Řehůřek <me@radimrehurek.com>

gensim/models/word2vec.py

@@ -1821,7 +1821,7 @@ def predict_output_word(self, context_words_list, topn=10):
             raise RuntimeError("Parameters required for predicting the output words not found.")
 
         if all(isinstance(w, int) for w in context_words_list):
-            # then, indices were passed. Check they are valid
+            # Integer indices were passed. Check that they are all valid.
             word2_indices = np.array(context_words_list)
             if np.any(word2_indices < 0):
                 logger.warning("All input context word indices must be non-negative.")
@@ -1832,7 +1832,7 @@ def predict_output_word(self, context_words_list, topn=10):
                 logger.warning("All the input context words are out-of-vocabulary for the current model.")
                 return None
         else:
-            # then, words were passed. Retrieve their indices
+            # Words (strings) were passed. Retrieve their indices.
             word2_indices = [self.wv.get_index(w) for w in context_words_list if w in self.wv]
             if not word2_indices:
                 logger.warning("All the input context words are out-of-vocabulary for the current model.")