DOC-4236 added HyperLogLog examples (redis#3117)

Co-authored-by: Vladyslav Vildanov <117659936+vladvildanov@users.noreply.github.com>

doctests/hll_tutorial_test.go

@@ -0,0 +1,75 @@
+// EXAMPLE: hll_tutorial
+// HIDE_START
+package example_commands_test
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/redis/go-redis/v9"
+)
+
+// HIDE_END
+
+func ExampleClient_pfadd() {
+	ctx := context.Background()
+
+	rdb := redis.NewClient(&redis.Options{
+		Addr:     "localhost:6379",
+		Password: "", // no password docs
+		DB:       0,  // use default DB
+	})
+
+	// REMOVE_START
+	rdb.Del(ctx, "bikes", "commuter_bikes", "all_bikes")
+	// REMOVE_END
+
+	// STEP_START pfadd
+	res1, err := rdb.PFAdd(ctx, "bikes", "Hyperion", "Deimos", "Phoebe", "Quaoar").Result()
+
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(res1) // 1
+
+	res2, err := rdb.PFCount(ctx, "bikes").Result()
+
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(res2) // 4
+
+	res3, err := rdb.PFAdd(ctx, "commuter_bikes", "Salacia", "Mimas", "Quaoar").Result()
+
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(res3) // 1
+
+	res4, err := rdb.PFMerge(ctx, "all_bikes", "bikes", "commuter_bikes").Result()
+
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(res4) // OK
+
+	res5, err := rdb.PFCount(ctx, "all_bikes").Result()
+
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(res5) // 6
+	// STEP_END
+
+	// Output:
+	// 1
+	// 4
+	// 1
+	// OK
+	// 6
+}