update docs

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

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

@@ -90,9 +90,9 @@ Use the following APIs to delete a  **Storage**  instance or data file.
    context.getFilesDir().then((filePath) => {
        path = filePath;
        console.info("======================>getFilesDirPromsie====================>");
-   });
        
        let promise = dataStorage.getStorage(path + '/mystore');
+   });
    ```
 
 
@@ -120,14 +120,15 @@ Use the following APIs to delete a  **Storage**  instance or data file.
 
    ```js
    promise.then((storage) => {
-        let getPromise = storage.get('startup', 'default');
+       let getPromise = storage.get('startup', 'default')
        getPromise.then((value) => {
            console.info("The value of startup is " + value);
        }).catch((err) => {
            console.info("Failed to get the value of startup with err: " + err);
        })
    }).catch((err) => {
-        console.info("Failed to get the storage.");
+       console.info("Failed to get the storage.")
+        
    })
    ```
 
@@ -149,7 +150,7 @@ Use the following APIs to delete a  **Storage**  instance or data file.
        var observer = function (key) {
            console.info("The key of " + key + " changed.");
        }
-        storage.on('change', observer);
+       storage.on('change', observer)
        storage.putSync('startup', 'auto'); // Modify data in the Storage instance.
        storage.flushSync(); // Trigger the StorageObserver callback.
     
@@ -169,7 +170,7 @@ Use the following APIs to delete a  **Storage**  instance or data file.
    promise.then(() => {
        console.info("Succeeded in deleting the storage.");
    }).catch((err) => {
-        console.info("Failed to deleted the storage with err: " + err);
+       console.info("Failed to delete the storage with err: " + err);
+        
    })
    ```
-