set_tutorial snippets (#197)

* set_tutorial snippets

* dotnet format

---------

Co-authored-by: shacharPash <shachar.pashchur@redis.com>
Co-authored-by: shacharPash <93581407+shacharPash@users.noreply.github.com>

tests/Doc/StringSnippets.cs

@@ -0,0 +1,81 @@
+// EXAMPLE: set_tutorial
+// HIDE_START
+
+//REMOVE_START
+
+using NRedisStack.Tests;
+using StackExchange.Redis;
+
+namespace NRedisStack.Doc;
+[Collection("DocsTests")]
+//REMOVE_END
+public class StringSnippets
+{
+    //REMOVE_START
+    [SkipIfRedis(Is.OSSCluster)]
+    //REMOVE_END
+    public void run()
+    {
+        var redis = ConnectionMultiplexer.Connect("localhost:6379");
+        var db = redis.GetDatabase();
+
+        //HIDE_END
+
+        //REMOVE_START
+        db.KeyDelete(new RedisKey[] { "bike:1", "bike:2", "bike:3", "total_crashes" });
+        //REMOVE_END
+
+        // STEP_START set_get
+        var res1 = db.StringSet("bike:1", "Deimos");
+        Console.WriteLine(res1); // true
+        var res2 = db.StringGet("bike:1");
+        Console.WriteLine(res2); // Deimos
+        // STEP_END
+
+        //REMOVE_START
+        Assert.True(res1);
+        Assert.Equal("Deimos", res2);
+        //REMOVE_END
+
+        //STEP_START setnx_xx
+        var res3 = db.StringSet("bike:1", "bike", when: When.NotExists);
+        Console.WriteLine(res3); // false
+        Console.WriteLine(db.StringGet("bike:1"));
+        var res4 = db.StringSet("bike:1", "bike", when: When.Exists);
+        Console.WriteLine(res4); // true
+        //STEP_END
+
+        //REMOVE_START
+        Assert.False(res3);
+        Assert.True(res4);
+        //REMOVE_END
+
+        //STEP_START mset
+        var res5 = db.StringSet(new KeyValuePair<RedisKey, RedisValue>[]
+        {
+            new ("bike:1", "Deimos"), new("bike:2", "Ares"), new("bike:3", "Vanth")
+        });
+        Console.WriteLine(res5);
+        var res6 = db.StringGet(new RedisKey[] { "bike:1", "bike:2", "bike:3" });
+        Console.WriteLine(res6);
+        //STEP_END
+
+        //REMOVE_START
+        Assert.True(res5);
+        Assert.Equal(new[] { "Deimos", "Ares", "Vanth" }, res6.Select(x => x.ToString()).ToArray());
+        //REMOVE_END
+
+        //STEP_START incr
+        db.StringSet("total_crashes", 0);
+        var res7 = db.StringIncrement("total_crashes");
+        Console.WriteLine(res7); // 1
+        var res8 = db.StringIncrement("total_crashes", 10);
+        Console.WriteLine(res8);
+        //STEP_END
+
+        //REMOVE_START
+        Assert.Equal(1, res7);
+        Assert.Equal(11, res8);
+        //REMOVE_END
+    }
+}