update docs

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

en/application-dev/database/database-mdds-guidelines.md

@@ -34,11 +34,14 @@ The following uses a single KV store as an example to describe the development p
    ```
 
 2. Create a **KvManager** instance based on the specified **KvManagerConfig** object.
+   
    (1) Create a **KvManagerConfig** object based on the application context.
+
    (2) Create a **KvManager** instance.
    
    The sample code is as follows:
-   ```js
+   
+   ```
    let kvManager;
    try {
        const kvManagerConfig = {
@@ -61,8 +64,11 @@ The following uses a single KV store as an example to describe the development p
    }
    ```
       
+   
 3. Create and obtain a single KV store.
+
    (1) Declare the ID of the single KV store to create.
+
    (2) Create a single KV store. You are advised to disable automatic synchronization (**autoSync:false**) and call **sync** when a synchronization is required.
 
    The sample code is as follows:
@@ -103,7 +109,9 @@ The following uses a single KV store as an example to describe the development p
    ```
 
 5. Write data to the single KV store.
+
    (1) Construct the key and value to be written into the single KV store.
+
    (2) Write key-value pairs into the single KV store.
 
    The following is the sample code for writing key-value pairs of the string type into the single KV store:
@@ -125,7 +133,9 @@ The following uses a single KV store as an example to describe the development p
    ```
 
 6. Query data in the single KV store.
+
    (1) Construct the key to be queried from the single KV store.
+
    (2) Query data from the single KV store.
 
    The following is the sample code for querying data of the string type from the single KV store:
@@ -155,7 +165,7 @@ The following uses a single KV store as an example to describe the development p
    >
    > The APIs of the `deviceManager` module are system interfaces.
 
-   The following is a code example for synchronizing data in a single KV store:
+   The following is the sample code for synchronizing data in a single KV store:
    ```js
    import deviceManager from '@ohos.distributedHardware.deviceManager';