message: add useDisclosure hook doc
diff: +import Head from "next/head";
  +
  +<Head key="useDisclosure">
  + <title key="tti">useDisclosure hook</title>
  +</Head>
  +
  +# useDisclosure
  +
  +`useDisclosure` is a custom hook to help handle common `open`, `close`, or
  +`toggle` scenarios. It can be used to control the display of components such as
  +[Drawer](/drawer), [Modal](/modal), [Toast](/toast) or [Alert](/alert).
  +
  +## Return value
  +
  +The `useDisclosure` hook returns an object with the following fields:
  +
  +| Name | Type | Default | Description |
  +| ---------- | ---------- | ------- | ------------------------------------------------------------------- |
  +| `isOpen` | `boolean` | `false` | If `true` set the controlled component to it's visible state. |
  +| `onClose` | `function` | | Callback function to set a falsy value for the `isOpen` parameter. |
  +| `onOpen` | `function` | | Callback function to set a truthy value for the `isOpen` parameter. |
  +| `onToggle` | `function` | | Callback function to toggle the value of the `isOpen` parameter. |
  +
  +## Installation
  +
  +```bash
  +npm install @chakra-ui/core
  +# or
  +yarn add @chakra-ui/core
  +```
  +
  +And then import the hook.
  +
  +```bash
  +import { useDisclosure } from "@chakra-ui/core";
  +```
  +
  +## Usage
  +
  +```jsx
  +function Example() {
  + const { isOpen, onToggle, onClose } = useDisclosure();
  +
  + return (
  + <>
  + <Button onClick={onToggle}>Open Drawer</Button>
  + <Drawer
  + zIndex="3"
  + size="xs"
  + isOpen={isOpen}
  + placement="left"
  + onClose={onClose}
  + />
  + </>
  + );
  +}
  +```
  