!23694 Rectify the arkts syntax 3

Merge pull request !23694 from 189******51/master

zh-cn/application-dev/quick-start/arkts-observed-and-objectlink.md

@@ -346,7 +346,7 @@ struct ViewB {
         (item: ClassA) => {
           ViewA({ label: `#${item.id}`, a: item })
         },
-        (item: ClassA) => item.id.toString()
+        (item: ClassA): string => item.id.toString()
       )
       // 使用@State装饰的数组的数组项初始化@ObjectLink，其中数组项是被@Observed装饰的ClassA的实例
       ViewA({ label: `ViewA this.arrA[first]`, a: this.arrA[0] })

zh-cn/application-dev/quick-start/arkts-prop.md

@@ -264,7 +264,7 @@ struct ParentComponent {
 ```ts
 @Component
 struct Child {
-  @Prop value: number;
+  @Prop value: number = 0;
 
   build() {
     Text(`${this.value}`)
@@ -288,10 +288,10 @@ struct Index {
         Divider().height(5)
 
         ForEach(this.arr, 
-          item => {
+          (item: void) => {
             Child({value: item})
           }, 
-          item => item.toString()
+          (item: string) => item.toString()
         )
         Text('replace entire arr')
         .fontSize(50)

zh-cn/application-dev/quick-start/arkts-rendering-control-best-practices.md

@@ -22,10 +22,10 @@ struct Index {
   build() {
       Column() {
        ForEach(this.arr,
-         (item) => {
+         (item: void) => {
            Text(`Item ${item}`)
          },
-         item => item.toString())
+         (item: string) => item.toString())
        Text('Add arr element')
          .fontSize(20)
          .onClick(()=>{
@@ -61,7 +61,7 @@ ForEach数据源更新时，数组项ID与原数组项ID重复不会重新创建
 ```ts
 @Component
 struct Child {
-  @Prop value: number;
+  @Prop value: number = 0;
   build() {
     Text(`${this.value}`)
       .fontSize(50)
@@ -83,10 +83,10 @@ struct Index {
         Child({ value: this.arr[2] })
         Divider().height(5)
         ForEach(this.arr,
-          item => {
+          (item: number) => {
             Child({ value: item })
           },
-          item => item.toString()  // 键值，标识id
+          (item: string) => item.toString()  // 键值，标识id
         )
         Text('Parent: replace entire arr')
           .fontSize(50)