Update hello-world.md

add missing chapter to ebook, fixing quii#427

mistake in example code

add missing chapters to epub

Update anti-patterns.md

Re-arranging things after some feedback

remove things from hello world, fixing quii#399

add links to anti-patterns chapter

Brief intro to comments and tiny formatting update. (quii#409)

* Add intro about comments after their first mention

* Add formatting to string for consistency
* Specific line has int highlighted just before it as well

typo

better sources