[Tutorial] autocomplete component example documentation bug

[acorncom]

From the Autocomplete Component step under the heading "An Integration Test" the second code listing for tests/integration/components/list-filter-test.js (19 lines of code), line 13 should be highlighted as green, because the async keyword has been added to the function declaration. Without it, the test fails once the await keyword is added in the next code example.

From emberjs/ember.js#16369