message: don't use UnderlineNavLink in main nav
diff: @@ -3,7 +3,7 @@ import PropTypes from 'prop-types'
  import {NavLink} from 'react-router-dom'
  import Styles from './doc-components/Styles'
  import Octicon, {Package} from '@github/octicons-react'
  -import {Link, Text, UnderlineNav, UnderlineNavLink} from '../src'
  +import {Link, Text, UnderlineNav} from '../src'
  import {name, repository, version} from '../package.json'
  const pkg = `${name}@${version}`
  @@ -22,15 +22,9 @@ export default function Page({render}) {
  </Text>
  }
  >
  - <UnderlineNavLink tag={NavLink} to="/components">
  - Components
  - </UnderlineNavLink>
  - <UnderlineNavLink tag={NavLink} to="/demos">
  - Demos
  - </UnderlineNavLink>
  - <UnderlineNavLink tag={NavLink} to="/sandbox">
  - Sandbox
  - </UnderlineNavLink>
  + <NavLink to="/components">Components</NavLink>
  + <NavLink to="/demos">Demos</NavLink>
  + <NavLink to="/sandbox">Sandbox</NavLink>
  </UnderlineNav>
  {render()}
  </div>
  