refactor: Replace 结点 with 节点 (#452)

* Replace 结点 with 节点
Update the footnotes in the figures

* Update mindmap

* Reduce the size of the mindmap.png

codes/go/chapter_searching/linear_search_test.go

@@ -22,5 +22,5 @@ func TestLinearSearch(t *testing.T) {
 	// 在链表中执行线性查找
 	head := ArrayToLinkedList(nums)
 	node := linearSearchLinkedList(head, target)
-	fmt.Println("目标结点值 3 的对应结点对象为", node)
+	fmt.Println("目标节点值 3 的对应节点对象为", node)
 }