【OpenHarmony开源贡献者计划2022】增加句尾标点，与前面保持风格一致

Signed-off-by: Luoyiling1010 <345725087@qq.com>
Signed-off-by: NLuoyiling1010 <345725087@qq.com>

en/contribute/OpenHarmony-64bits-coding-guide.md

@@ -404,8 +404,8 @@ typedef struct {
 } TreeNodeInfo;
 
 typedef struct {
-    TreeNodeInfo nodeInfo;   /* Tree information data structure of each node */
-    void *userInfo;          /* User information data structure of each node */
+    TreeNodeInfo nodeInfo;   /* Tree information data structure of each node. */
+    void *userInfo;          /* User information data structure of each node. */
 } TreeNode;
 ```