refactor(docs-infra): fix docs examples for tslint rule only-arrow-functions (#38143)

This commit updates the docs examples to be compatible with the
`only-arrow-functions` tslint rule.

This is in preparation of updating the docs examples `tslint.json` to
match the one generated for new Angular CLI apps in a future commit.

PR Close #38143

aio/content/examples/providers/e2e/src/app.e2e-spec.ts

@@ -27,7 +27,7 @@ describe('providers App', () => {
   });
 
 
-  it('shows a list of customers', function() {
+  it('shows a list of customers', () => {
     const list = getListSectionStruct();
     expect(list.items.count()).toBe(10);
     expect(list.items.get(0).getText()).toBe('1 Maria');