docs(collapse): modify the accordion attribute text to be easier to understand (#7612)

Author: cc-hearts

components/collapse/index.en-US.md

@@ -20,7 +20,7 @@ A content area which can be collapsed and expanded.
 | Property | Description | Type | Default | Version |
 | --- | --- | --- | --- | --- |
 | accordion | If `true`, `Collapse` renders as `Accordion` | boolean | `false` |  |
-| activeKey(v-model) | Key of the active panel | string\[] \| string <br> number\[] \| number | No default value. In `accordion` mode, it's the key of the first panel. |  |
+| activeKey(v-model) | Key of the active panel | string\[] \| string <br> number\[] \| number | No default value. In [accordion mode](#components-collapse-demo-accordion), it's the key of the first panel. |  |
 | bordered | Toggles rendering of the border around the collapse block | boolean | `true` |  |
 | collapsible | Specify whether the panels of children be collapsible or the trigger area of collapsible | `header` \| `icon` \| `disabled` | - | 4.0 |
 | destroyInactivePanel | Destroy Inactive Panel | boolean | `false` |  |

components/collapse/index.zh-CN.md

@@ -20,8 +20,8 @@ coverDark: https://mdn.alipayobjects.com/huamei_7uahnr/afts/img/A*sir-TK0HkWcAAA
 
 | 参数 | 说明 | 类型 | 默认值 | 版本 |
 | --- | --- | --- | --- | --- |
-| accordion | 手风琴模式 | boolean | `false` |  |
-| activeKey(v-model) | 当前激活 tab 面板的 key | string\[] \| string <br> number\[] \| number | 默认无，accordion 模式下默认第一个元素 |  |
+| accordion | 手风琴模式，始终只有一个面板处在激活状态 | boolean | `false` |  |
+| activeKey(v-model) | 当前激活 tab 面板的 key | string\[] \| string <br> number\[] \| number | 默认无，[手风琴模式](#components-collapse-demo-accordion)下默认第一个元素 |  |
 | bordered | 带边框风格的折叠面板 | boolean | `true` |  |
 | collapsible | 所有子面板是否可折叠或指定可折叠触发区域 | `header` \| `icon` \| `disabled` | - | 4.0 |
 | destroyInactivePanel | 销毁折叠隐藏的面板 | boolean | `false` |  |