Use https everywhere, replace broken anchor links with working
alternatives. Reword paragraph mentioning DoctrineExtensions
adding links to actual package and bundle documentation.

Avoid words like 'just', 'simply' and making any assumptions
about knowledge of a user. Replace 'easiest' with 'recommended'.

Avoid repetitions of words, use punctuation marks in proper places.

Replace Acme bundles with App. Remove generate:bundle command.

Update file paths to new directory structure. Update installation guide
to cover required steps when not using Flex. Prefer project_dir over root_dir.

Reorder `use` statements, prefer [] over array(). Fix typos. Remove duplicated
DefaultController example as the first one includes autowired DocumentManager
already. Remove dynamic findOneBy methods examples.

UserInterface anchor no longer exists in Symfony docs - linking to Security.