Fix issue 329 clearer package indication

[Insaynoah]

I added some clearer package indication. There are also a bunch of minor change to improve readability of the OMA book:

• A lot of the times, lines in code blocks where way too long so you had to scroll. This should be better now.
• fixed some typos, sentence structures etc

I'll definitely work more on the readability and let me know if there's anything i need to watch out for when improving readability.