Add vad with non-streaming ASR examples for Dart API (#1180)

dart-api-examples/README.md

@@ -5,6 +5,17 @@ This directory contains examples for Dart API.
 You can find the package at
 https://pub.dev/packages/sherpa_onnx
 
+## Descirption
+
+| Directory | Description |
+|-----------|-------------|
+| [./keyword-spotter](./keyword-spotter)| Example for keyword spotting|
+| [./non-streaming-asr](./non-streaming-asr)| Example for non-streaming speech recognition|
+| [./streaming-asr](./streaming-asr)| Example for streaming speech recognition|
+| [./tts](./tts)| Example for text to speech|
+| [./vad](./vad)| Example for voice activity detection|
+| [./vad-with-non-streaming-asr](./vad-with-non-streaming-asr)| Example for voice activity detection with non-streaming speech recognition. You can use it to generate subtitles.|
+
 ## How to create an example in this folder
 
 ```bash