fix(gatsby-theme-docz): wrong imports

Author: pedronauck

Diff for: core/gatsby-theme-docz/src/components/Sidebar/index.js

@@ -1,6 +1,5 @@
 /** @jsx jsx */
-/** @jsxFrag React.Fragment */
-import React, { forwardRef, useState, useRef, useEffect } from 'react'
+import { Fragment, forwardRef, useState, useRef, useEffect } from 'react'
 import { Global } from '@emotion/react'
 import { jsx, Box } from 'theme-ui'
 import { useMenus, useCurrentDoc } from 'docz'