support whisper language (#678)

@@ -298,6 +298,9 @@ SherpaOnnxOfflineRecognizer *CreateOfflineRecognizer(
   recognizer_config.model_config.whisper.decoder =
       SHERPA_ONNX_OR(config->model_config.whisper.decoder, "");
 
+  recognizer_config.model_config.whisper.language =
+      SHERPA_ONNX_OR(config->model_config.whisper.language, "");
+
   recognizer_config.model_config.tdnn.model =
       SHERPA_ONNX_OR(config->model_config.tdnn.model, "");
 

@@ -332,6 +332,7 @@ SHERPA_ONNX_API typedef struct SherpaOnnxOfflineNemoEncDecCtcModelConfig {
 SHERPA_ONNX_API typedef struct SherpaOnnxOfflineWhisperModelConfig {
   const char *encoder;
   const char *decoder;
+  const char *language;
 } SherpaOnnxOfflineWhisperModelConfig;
 
 SHERPA_ONNX_API typedef struct SherpaOnnxOfflineTdnnModelConfig {