Fix minor typos and improve grammar and code formatting

[ci skip]
I think we can improve this even more, what do you think about:
"The above code will load all  the comments and all of their associated authors and gravatars"

While we're in here I think the rest of this section can be improved as well. :smile: 
"You can mix and match any combination of symbols, arrays, and hashes to retrieve the associations you want to load."