Upgrade all rehype and remark (#43021)

tests/rendering/annotate.js

@@ -18,6 +18,8 @@ describe('annotate', () => {
     // We don't normally use snapshots,
     // but in this case its a short and concise example
     // that won't change regularly.
+    // If it fails, study the output and make sure it's correct.
+    // If it is indeed correct, run `jest --updateSnapshot` to update it.
     expect(await renderContent(example)).toMatchSnapshot()
   })
 })