message: Use functional variables in documentation for Grid
diff: @@ -8,8 +8,12 @@ Grid is a component that exposes grid system props. See the [CSS Tricks Complete
  ```jsx live
  <Grid gridTemplateColumns="repeat(2, auto)" gridGap={3}>
  - <Box p={3} bg="blue.2">1</Box>
  - <Box p={3} bg="yellow.2">2</Box>
  + <Box p={3} bg="bg.info">
  + 1
  + </Box>
  + <Box p={3} bg="bg.warning">
  + 2
  + </Box>
  </Grid>
  ```
  