fix docs bug

Signed-off-by: https://gitee.com/WALL_EYE <wangguoqiang12@huawei.com>
Change-Id: Ie2152781ea8a4bc9c466307921b5886bb6f4637f

zh-cn/application-dev/security/userauth-guidelines-api6.md

@@ -38,11 +38,9 @@ userIAM_userAuth模块提供了用户认证的相关方法，包括获取认证
 
    ```js
    let authenticator = userIAM_userAuth.getAuthenticator();
-   authenticator.execute("FACE_ONLY", "S2").then((code)=>{
-       authenticator.off("tip", tipCallback);
+   authenticator.execute("FACE_ONLY", "S2").then((code) => {
        console.info("auth success");
-   }).catch((code)=>{
-       authenticator.off("tip", tipCallback);
+   }).catch((code) => {
        console.error("auth fail, code = " + code);
    });
    ```

zh-cn/application-dev/security/userauth-guidelines-api8.md

@@ -93,6 +93,7 @@ userIAM_userAuth模块提供了用户认证的相关方法，包括检测认证
 5. 认证过程中取消认证，代码示例如下：
 
    ```js
+   let auth = new userIAM_userAuth.UserAuth();
    // contextId通过auth接口获取
    let contextId = auth.auth(null, userIAM_userAuth.UserAuthType.FACE, userIAM_userAuth.AuthTrustLevel.ATL1, {
        onResult: (result, extraInfo) => {

zh-cn/application-dev/security/userauth-guidelines-api8.md.bak

@@ -93,6 +93,7 @@ userIAM_userAuth模块提供了用户认证的相关方法，包括检测认证
 5. 认证过程中取消认证，代码示例如下：
 
    ```js
+   let auth = new userIAM_userAuth.UserAuth();
    // contextId通过auth接口获取
    let contextId = auth.auth(null, userIAM_userAuth.UserAuthType.FACE, userIAM_userAuth.AuthTrustLevel.ATL1, {
        onResult: (result, extraInfo) => {