message: docs: update migration guide about color mode
diff: @@ -196,6 +196,16 @@ types and accessibility.
  - All components now take the pseudo style props (`_hover`, `_active`, etc.)
  - Improved TypeScript support for the `as` prop
  +### Color mode
  +
  +We changed the signature of the `useColorMode` hook to use array destructuing
  +instead of object destructuing.
  +
  +```diff
  +- const { colorMode, toggleMode } = useColorMode()
  ++ const [ colorMode, toggleMode ] = useColorMode()
  +```
  +
  ### Accordion
  Can install as a stand-alone package: `@chakra-ui/accordion`
  