message: fix Heading lint errors
diff: /* eslint-disable jsx-a11y/heading-has-content */
  import React from 'react'
  import {Heading} from '..'
  -import {render, renderStyles} from '../utils/testing'
  +import {render} from '../utils/testing'
  const theme = {
  breakpoints: ['400px', '640px', '960px', '1280px'],
  