Changes

• cd152e7 Update @types/unist
  migrate: update @types/unist too
• 8a2febe Change to require Node.js 16
  migrate: update Node
• f91a1c2 Change to use export map
  migrate: don’t use private APIs
• dc59467 Change types to work w/o explicit type parameter
  migrate: don’t pass an explicit type parameter;
  replace AssertAnything, AssertPredicate -> Check;
  TestFunctionAnything, TestFunctionPredicate -> TestFunction;
  PredicateTest -> Test

Full Changelog: 5.2.1...6.0.0