message: docs(color-mode): add info about `system` config option
diff: @@ -23,6 +23,12 @@ To get dark mode working correctly, you need to do two things:
  your application should start with to either `light`, `dark` or `system`. It
  is `light` by default.
  +> **Note:** When using `system` as initial color mode, the theme will change
  +> with the system preference. However, if another theme is manually selected by
  +> the user then that theme will be used on the next page load. To reset it to
  +> system preference, simply remove the `chakra-ui-color-mode` entry from
  +> localStorage.
  +
  ### Updating the theme config
  The theme config for color mode has 2 options:
  @@ -74,7 +80,7 @@ export default theme
  ### Adding the `ColorModeScript`
  -The color mode script needs to added before the `body` tag for local storage
  +The color mode script needs to be added before the content inside the `body` tag for local storage
  syncing to work correctly.
  > When setting the initial color mode, we recommend adding it as a config to
  