Add doc (14270)

Signed-off-by: Nester.zhou <ester.zhou@huawei.com>

en/release-notes/changelogs/OpenHarmony_3.2.10.1/changelog-LocalStorage.md

+# ArkUI Subsystem LocalStorage Class ChangeLog 
+
+## cl.LocalStorage.1 Return Type Change of the get API
+
+Changed the return type from **get\<T>(propName: string): T** to **get\<T>(propName: string): T | undefined**.
+
+**Change Impact**
+
+
+None
+
+## cl.LocalStorage.2 Mandatory/Optional Change of the newValue Parameter in setOrCreate
+**Change Impact**
+
+API declaration before change:
+```js
+setOrCreate<T>(propName: string, newValue?: T): boolean
+```
+API declaration after change:
+```js
+setOrCreate<T>(propName: string, newValue: T): boolean
+```
+The **newValue** parameter becomes mandatory.
+If it is not specified when an application calls the API, the build will fail after the SDK is replaced.
+
+**Adaptation Guide**
+
+```js
+let storage = new LocalStorage();
+storage.setOrCreate('propA', 'hello');
+```
+## cl.LocalStorage.3 link Parameter and Return Type Changes
+**Change Impact**
+
+API declaration before change:
+```js
+link<T>(propName: string, linkUser?: T, subscribersName?: string): T
+```
+API declaration after change:
+```js
+link<T>(propName: string): SubscribedAbstractProperty<T>
+```
+1. The second and third parameters of the **link** API are reserved for internal use by the framework. Therefore, the API is changed to contain only one parameter.
+2. The return type **T** is changed to **SubscribedAbstractProperty**.
+
+**Adaptation Guide**
+
+```js
+let storage = new LocalStorage({"PropA": "47"});
+let linA = storage.link("PropA");
+linA.set(50);
+```
+
+## cl.LocalStorage.4 setAndLink Parameter and Return Type Changes
+**Change Impact**
+
+API declaration before change:
+```js
+setAndLink<T>(propName: string, defaultValue: T, linkUser?: T, subscribersName?: string): T
+```
+API declaration after change:
+```js
+setAndLink<T>(propName: string, defaultValue: T): SubscribedAbstractProperty<T>
+```
+1. The third and fourth parameters of the **setAndLink** API are reserved for internal use by the framework. Therefore, the API is changed to contain two parameters.
+2. The return type **T** is changed to **SubscribedAbstractProperty**.
+
+**Adaptation Guide**
+
+```js
+let storage = new LocalStorage({"PropA": "47"});
+let linA = storage.setAndLink("PropA", "48")
+linA.set(50);
+```
+
+## cl.LocalStorage.5 prop Parameter and Return Type Changes
+**Change Impact**
+
+API declaration before change:
+```js
+prop<T>(propName: string, propUser?: T, subscribersName?: string): T
+```
+API declaration after change:
+```js
+prop<S>(propName: string): SubscribedAbstractProperty<S>
+```
+1. The second and third parameters of the **prop** API are reserved for internal use by the framework. Therefore, the API is changed to contain only one parameter.
+2. The return type **T** is changed to **SubscribedAbstractProperty**.
+
+**Adaptation Guide**
+
+```js
+let storage = new LocalStorage({"PropA": "47"});
+let propA = storage.prop("PropA");
+propA.set(51); // one-way sync
+```
+
+## cl.LocalStorage.6 setAndProp Parameter and Return Type Changes
+**Change Impact**
+
+API declaration before change:
+```js
+setAndProp<T>(propName: string, defaultValue: T, propUser?: T, subscribersName?: string): T
+```
+API declaration after change:
+```js
+setAndProp<S>(propName: string, defaultValue: S): SubscribedAbstractProperty<S>
+```
+1. The third and fourth parameters of the **setAndProp** API are reserved for internal use by the framework. Therefore, the API is changed to contain two parameters.
+2. The return type **T** is changed to **SubscribedAbstractProperty**.
+
+**Adaptation Guide**
+
+```js
+let storage = new LocalStorage({"PropA": "47"});
+let propA = storage.setAndProp("PropA", "48");
+propA.set(51); // one-way sync
+```