Wrap punctuation APIs to C#. (#945)

dotnet-examples/offline-punctuation/Program.cs

@@ -0,0 +1,45 @@
+// Copyright (c)  2024  Xiaomi Corporation
+//
+// This file shows how to add punctuations to text.
+//
+// 1. Download a model from
+// https://github.com/k2-fsa/sherpa-onnx/releases/tag/punctuation-models
+//
+// wget https://github.com/k2-fsa/sherpa-onnx/releases/download/punctuation-models/sherpa-onnx-punct-ct-transformer-zh-en-vocab272727-2024-04-12.tar.bz2
+//
+// 3. Now run it
+//
+// dotnet run
+
+using SherpaOnnx;
+using System.Collections.Generic;
+using System;
+
+class OfflinePunctuationDemo
+{
+
+  static void Main(string[] args)
+  {
+    var config = new OfflinePunctuationConfig();
+    config.Model.CtTransformer = "./sherpa-onnx-punct-ct-transformer-zh-en-vocab272727-2024-04-12/model.onnx";
+    config.Model.Debug = 1;
+    config.Model.NumThreads = 1;
+    var punct = new OfflinePunctuation(config);
+
+    string[] textList = new string[] {
+        "这是一个测试你好吗How are you我很好thank you are you ok谢谢你",
+        "我们都是木头人不会说话不会动",
+        "The African blogosphere is rapidly expanding bringing more voices online in the form of commentaries opinions analyses rants and poetry",
+    };
+
+    Console.WriteLine("---------");
+    foreach (string text in textList)
+    {
+      string textWithPunct = punct.AddPunct(text);
+      Console.WriteLine("Input text: {0}", text);
+      Console.WriteLine("Output text: {0}", textWithPunct);
+      Console.WriteLine("---------");
+    }
+  }
+}
+