feat(Sticky): offset-top support vh unit (#7498)

src/area/README.md

@@ -65,7 +65,7 @@ To have a selected value，simply pass the `code` of target area to `value` prop
 | columns-placeholder | Placeholder of columns | _string[]_ | `[]` |
 | loading | Whether to show loading prompt | _boolean_ | `false` |
 | readonly `v2.10.5` | Whether to be readonly | _boolean_ | `false` |
-| item-height `v2.8.6` | Option height, supports `px` `vw` `rem` unit, default `px` | _number \| string_ | `44` |
+| item-height `v2.8.6` | Option height, supports `px` `vw` `vh` `rem` unit, default `px` | _number \| string_ | `44` |
 | columns-num | Level of picker | _number \| string_ | `3` |
 | visible-item-count | Count of visible columns | _number \| string_ | `6` |
 | swipe-duration | Duration of the momentum animation，unit `ms` | _number \| string_ | `1000` |

src/area/README.zh-CN.md

@@ -65,7 +65,7 @@ Vue.use(Area);
 | columns-placeholder | 列占位提示文字 | _string[]_ | `[]` |
 | loading | 是否显示加载状态 | _boolean_ | `false` |
 | readonly `v2.10.5` | 是否为只读状态，只读状态下无法切换选项 | _boolean_ | `false` |
-| item-height `v2.8.6` | 选项高度，支持 `px` `vw` `rem` 单位，默认 `px` | _number \| string_ | `44` |
+| item-height `v2.8.6` | 选项高度，支持 `px` `vw` `vh` `rem` 单位，默认 `px` | _number \| string_ | `44` |
 | columns-num | 显示列数，3-省市区，2-省市，1-省 | _number \| string_ | `3` |
 | visible-item-count | 可见的选项个数 | _number \| string_ | `6` |
 | swipe-duration | 快速滑动时惯性滚动的时长，单位`ms` | _number \| string_ | `1000` |