Support getting word IDs for CTC HLG decoding. (#978)

sherpa-onnx/csrc/online-ctc-decoder.h

@@ -22,8 +22,16 @@ struct OnlineCtcDecoderResult {
   /// The decoded token IDs
   std::vector<int64_t> tokens;
 
+  /// The decoded word IDs
+  /// Note: tokens.size() is usually not equal to words.size()
+  /// words is empty for greedy search decoding.
+  /// it is not empty when an HLG graph or an HLG graph is used.
+  std::vector<int32_t> words;
+
   /// timestamps[i] contains the output frame index where tokens[i] is decoded.
   /// Note: The index is after subsampling
+  ///
+  /// tokens.size() == timestamps.size()
   std::vector<int32_t> timestamps;
 
   int32_t num_trailing_blanks = 0;