7.0.0

Change

• ebf43e7 Update unified, @types/hast, utilities, etc
  migrate: update too
• 3cf2c29 Change to require Node.js 16
  migrate: update too
• f9fab12 Change to use exports
  migrate: don’t use private APIs
• 6724645 rehype-minify-doctype: remove
  migrate: it’s not possible to use weird doctypes, use xast if you want xml
• 1635e2f hast-util-from-string: remove return value
  migrate: keep a reference to the changed node around

Full Changelog: 6.0.0...7.0.0