update readme, test=doc

demos/speech_server/README.md

@@ -15,7 +15,7 @@ You can choose one way from meduim and hard to install paddlespeech.
 
 ### 2. Prepare config File
 The configuration file can be found in `conf/application.yaml` .
-Among them, `engine_list` indicates the speech engine that will be included in the service to be started, in the format of speech task_engine type.
+Among them, `engine_list` indicates the speech engine that will be included in the service to be started, in the format of `<speech task>_<engine type>`.
 At present, the speech tasks integrated by the service include: asr (speech recognition), tts (text to sppech) and cls (audio classification).
 Currently the engine type supports two forms: python and inference (Paddle Inference)