message: [Docs]: fix incorrect module for mode method
  The `mode` method is in `/theme-tools`, not `/core`.
diff: @@ -143,7 +143,7 @@ styles can be a style object or a function that returns a style object.
  ```jsx live=false
  // theme.js
  import { extendTheme } from "@chakra-ui/core"
  -import { mode } from "@chakra-ui/core"
  +import { mode } from "@chakra-ui/theme-tools"
  // Version 1: Using objects
  const theme = extendTheme({
  