link is very deep down on acessibility page this commit is part of a larger effort to standardise ownload sections on angular.io
This commit partially addresses #35459
PR Close#36561
This PR adds the following links to web.dev/angular:
1. Link to the guides in the resource section under "Online Training"
2. Links to code-splitting & preloading in the lazy-loading guide
3. Link to the accessibility guide on web.dev/angular
PR Close#31804