These changes include
- Remove the usage of `enableProdMode`
- Remove `test.ts`, `polyfills.ts`, `karma.conf.js` and environment files which are no longer generated by default
PR Close#47904
add types to all the buttons in the angular.io examples to encourage
the best practice of always including a type per button (regardless
to whether it is in a form or now)
PR Close#44557
Content projection is an important part of Angular. However, it has
never been documented in the Angular documentation set. This topic
attempts to provide the basics of content projection for developers. It
is not a comprehensive guide; rather, it is a starting point that we
can hopefully expand upon in the future.
PR Close#41143
