docs(components): [virtualized-table] finishing leftovers (#7496)

- Finishing the documentation examples
- Add APIs to the documentation
- Fix some issue while updating the documentations

docs/examples/table-v2/basic.vue

@@ -1,11 +1,41 @@
 <template>
-  <table-v2 :columns="columns" :data="data" :width="700" :height="400" fixed />
+  <el-table-v2
+    :columns="columns"
+    :data="data"
+    :width="700"
+    :height="400"
+    fixed
+  />
 </template>
 
 <script lang="ts" setup>
-import TableV2 from '@element-plus/components/table-v2/src/table-v2'
-import { generateColumns, generateData } from './utils'
+const generateColumns = (length = 10, prefix = 'column-', props?: any) =>
+  Array.from({ length }).map((_, columnIndex) => ({
+    ...props,
+    key: `${prefix}${columnIndex}`,
+    dataKey: `${prefix}${columnIndex}`,
+    title: `Column ${columnIndex}`,
+    width: 150,
+  }))
+
+const generateData = (
+  columns: ReturnType<typeof generateColumns>,
+  length = 200,
+  prefix = 'row-'
+) =>
+  Array.from({ length }).map((_, rowIndex) => {
+    return columns.reduce(
+      (rowData, column, columnIndex) => {
+        rowData[column.dataKey] = `Row ${rowIndex} - Col ${columnIndex}`
+        return rowData
+      },
+      {
+        id: `${prefix}${rowIndex}`,
+        parentId: null,
+      }
+    )
+  })
 
 const columns = generateColumns(10)
-const data = generateData(columns, 1000)
+const data = generateData(columns, 200)
 </script>