docs: add 'sortDirections' description to Table component (#15461)

components/table/index.en-US.md

@@ -127,6 +127,7 @@ One of the Table `columns` prop for describing the table's columns, Column has t
 | render | Renderer of the table cell. The return value should be a ReactNode, or an object for [colSpan/rowSpan config](#components-table-demo-colspan-rowspan) | Function(text, record, index) {} | - |
 | sorter | Sort function for local sort, see [Array.sort](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort)'s compareFunction. If you need sort buttons only, set to `true` | Function\|boolean | - |
 | sortOrder | Order of sorted values: `'ascend'` `'descend'` `false` | boolean\|string | - |
+| sortDirections | supported sort way, could be `'ascend'`, `'descend'` | Array | `['ascend', 'descend']` |
 | title | Title of this column | ReactNode\|({ sortOrder, filters }) => ReactNode | - |
 | width | Width of this column | string\|number | - |
 | onCell | Set props on per cell | Function(record, rowIndex) | - |

components/table/index.zh-CN.md

@@ -132,6 +132,7 @@ const columns = [{
 | render | 生成复杂数据的渲染函数，参数分别为当前行的值，当前行数据，行索引，@return里面可以设置表格[行/列合并](#components-table-demo-colspan-rowspan) | Function(text, record, index) {} | - |
 | sorter | 排序函数，本地排序使用一个函数(参考 [Array.sort](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort) 的 compareFunction)，需要服务端排序可设为 true | Function\|boolean | - |
 | sortOrder | 排序的受控属性，外界可用此控制列的排序，可设置为 `'ascend'` `'descend'` `false` | boolean\|string | - |
+| sortDirections | 支持的排序方式，取值为 `'ascend'` `'descend'` | Array | `['ascend', 'descend']` |
 | title | 列头显示文字 | ReactNode\|({ sortOrder, filters }) => ReactNode | - |
 | width | 列宽度 | string\|number | - |
 | onCell | 设置单元格属性 | Function(record, rowIndex) | - |