Add Go codes to docs, including

the chapter of stack and queue, the chapter of tree.

codes/go/chapter_searching/linear_search_test.go

@@ -5,6 +5,7 @@
 package chapter_searching
 
 import (
+	"fmt"
 	"testing"
 
 	. "github.com/krahets/hello-algo/pkg"
@@ -16,10 +17,10 @@ func TestLinearSearch(t *testing.T) {
 
 	// 在数组中执行线性查找
 	index := linerSearchArray(nums, target)
-	t.Log("目标元素 3 的索引 =", index)
+	fmt.Println("目标元素 3 的索引 =", index)
 
 	// 在链表中执行线性查找
 	head := ArrayToLinkedList(nums)
 	node := linerSearchLinkedList(head, target)
-	t.Log("目标结点值 3 的对应结点对象为", node)
+	fmt.Println("目标结点值 3 的对应结点对象为", node)
 }