Revising the Portuguese course

[luizcdc]

Hello, everyone!

Firstly, I'd like to give my most sincere thanks for the work of this course's creators and contributors, especially @ines and @Cristianasp, who translated it into Portuguese.

I had a blast learning to use spaCy interactively, and it really is an incredible learning resource that I can't believe is free for everyone!

Throughout my journey with the course in Portuguese, I've noticed a few uncontroversial typos that I took note of. This PR contains all the typos that I was able to identify, plus a few more caught by Llama 3 (that I've manually vetted, of course).

I hope this contributes to improving the course and making it more accessible for future learners who speak my mother tongue.

Thanks again!