build(docs-infra): remove the `only-arrow-functions` tslint rule to align with CLI (#39018)

This commit removes the `only-arrow-functions: false` tslint rule to
more closely align `tslint.json` with the one generated by the latest
Angular CLI for new apps.

PR Close #39018

aio/src/app/search/search.worker.ts

@@ -44,7 +44,7 @@ function handleMessage(message: { data: WebWorkerMessage }): void {
   const payload = message.data.payload;
   switch (type) {
     case 'load-index':
-      makeRequest(SEARCH_TERMS_URL, function(searchInfo: PageInfo[]) {
+      makeRequest(SEARCH_TERMS_URL, (searchInfo: PageInfo[]) => {
         index = createIndex(loadIndex(searchInfo));
         postMessage({ type, id, payload: true });
       });
@@ -94,7 +94,7 @@ function queryIndex(query: string): PageInfo[] {
         results = index.search(query + ' ' + titleQuery);
       }
       // Map the hits into info about each page to be returned as results
-      return results.map(function(hit) { return pages[hit.ref]; });
+      return results.map(hit => pages[hit.ref]);
     }
   } catch (e) {
     // If the search query cannot be parsed the index throws an error

aio/tests/e2e/src/api-pages.e2e-spec.ts

@@ -1,6 +1,6 @@
 import { ApiPage } from './api.po';
 
-describe('Api pages', function() {
+describe('Api pages', () => {
   it('should show direct subclasses of a class', () => {
     const page = new ApiPage('api/forms/AbstractControlDirective');
     expect(page.getDescendants('class', true)).toEqual(['ControlContainer', 'NgControl']);

aio/tests/e2e/src/app.e2e-spec.ts

@@ -1,7 +1,7 @@
 import { browser, by, element, ElementFinder } from 'protractor';
 import { SitePage } from './app.po';
 
-describe('site App', function() {
+describe('site App', () => {
   let page: SitePage;
 
   beforeEach(() => {

aio/tests/e2e/src/onerror.e2e-spec.ts

@@ -3,7 +3,7 @@ import { SitePage } from './app.po';
 
 /* tslint:disable:max-line-length */
 
-describe('onerror handler', function() {
+describe('onerror handler', () => {
   let page: SitePage;
 
   beforeAll(() => {
@@ -186,7 +186,7 @@ createViewNodes@???`);
   });
 
   async function callOnError(message: string, url?: string, line?: number, column?: number, error?: Error) {
-    await browser.executeScript(function() {
+    await browser.executeScript(() => {
       // reset the ga queue
       (window as any).ga.q.length = 0;
       // post the error to the handler

aio/tslint.json

@@ -68,7 +68,6 @@
       true,
       "as-needed"
     ],
-    "only-arrow-functions": false,
     "quotemark": [
       true,
       "single"