update docs

Signed-off-by: NAnnie_wang <annie.wangli@huawei.com>

en/device-dev/subsystems/subsys-xts-guide.md

@@ -110,7 +110,6 @@ HCTest and the C language are used to develop test cases. HCTest is enhanced and
    │ │ └── BUILD.gn
    ```
    
-
 2. Write the test case in the **src** directory.
 
    (1) Include the test framework header file.
@@ -130,29 +129,25 @@ HCTest and the C language are used to develop test cases. HCTest is enhanced and
    */
    LITE_TEST_SUIT(test, example, IntTestSuite);
    ```
-
    (3) Define Setup and TearDown.
 
-      Format: Test suite name+Setup, Test suite name+TearDown.
-	  The Setup and TearDown functions must exist, but function bodies can be empty.  
+   ​      Format: Test suite name+Setup, Test suite name+TearDown.
 
-   (4) Use the **LITE_TEST_CASE** macro to write the test case.
+   ​      The Setup and TearDown functions must exist, but function bodies can be empty.    
 
-      Three parameters are involved: test suite name, test case name, and test case properties (including type, granularity, and level).
+   (4) Use the **LITE_TEST_CASE** macro to write the test case.
 
+   ​      Three parameters are involved: test suite name, test case name, and test case properties (including type, granularity, and level).
     ```
     LITE_TEST_CASE(IntTestSuite, TestCase001, Function | MediumTest | Level1) 
      {
      // Do something.
       };
     ```
-	
    (5) Use the **RUN_TEST_SUITE** macro to register the test suite.      
-
     ```
     RUN_TEST_SUITE(IntTestSuite);
     ```
-
 3. Create the configuration file (**BUILD.gn**) of the test module.
 
    Create a **BUILD.gn** (example) file in each test module directory, and specify the name of the built static library and its dependent header files and libraries.