message: Add link to jest
diff: @@ -91,7 +91,7 @@ Only static assets which are `import` 'ed into your application will be included
  === Testing
  To run the tests, the standard command `npm test` is valid,
  -but since some tests are using snapshots the preferred command is to update them in the same time:
  +but since some tests are using link:https://facebook.github.io/jest/docs/en/snapshot-testing.html[snapshots] the preferred command is to update them in the same time:
  [source,shell]
  ----
  npm test -- -u
  