message: docs: update style props for group
diff: @@ -328,7 +328,15 @@ import { Box } from "@chakra-ui/core"
  ### Shadow
  ```jsx
  -<SimpleGrid bg="gray.50" columns="4" spacing="8" p="10" textAlign="center" rounded="lg" color="gray.400">
  +<SimpleGrid
  + bg="gray.50"
  + columns="4"
  + spacing="8"
  + p="10"
  + textAlign="center"
  + rounded="lg"
  + color="gray.400"
  +>
  <Box boxShadow="xs" p="6" rounded="md" bg="white">
  xs
  </Box>
  @@ -363,7 +371,7 @@ import { Box } from "@chakra-ui/core"
  ```
  ```jsx
  -<Text textShadow="2px 2px #ff0000" boxShadow="5px 10px #999" m="6">
  +<Text textShadow="1px 1px #ff0000" m="6">
  Text with shadows
  </Text>
  ```
  @@ -433,12 +441,12 @@ import { Button } from "@chakra-ui/core"
  | `_visited` | `:visited` | none |
  | `_activeLink` | `[aria-current=page]` | none |
  | `_indeterminate` | `:indeterminate`,<br/>`[aria-checked=mixed]`,<br/>`[data-indeterminate]` | none |
  -| `_groupHover` | `` | none |
  -| `_groupFocus` | `` | none |
  -| `_groupActive` | `` | none |
  -| `_groupDisabled` | `` | none |
  -| `_groupInvalid` | `` | none |
  -| `_groupChecked` | `` | none |
  +| `_groupHover` | `[role=group]:hover &`, <br/> `[role=group][data-hover] &` | none |
  +| `_groupFocus` | `[role=group]:focus &`, <br/> `[role=group][data-focus] &` | none |
  +| `_groupActive` | `[role=group]:active &`, <br/> `[role=group][data-active] &` | none |
  +| `_groupDisabled` | `[role=group]:disabled &`, <br/> `[role=group][data-disabled] &` | none |
  +| `_groupInvalid` | `[role=group][data-invalid] &` | none |
  +| `_groupChecked` | `[role=group][data-checked] &` | none |
  | `_placeholder` | `::placeholder` | none |
  | `_fullScreen` | `:fullscreen` | none |
  | `_selection` | `::selection` | none |
  