When you find something not correct in grammatical point of view, you can edit it in a proper way, because it will benefit you, I mean, you’ll gain more reputations if you edit someone’s post in a proper way. That’s the main reason for this message:
Tiny, trivial edits are discouraged- try to make the post significantly better when you edit, correcting all problems that you observe.
I don’t think you need the section “when should I edit posts” because, you can search any post you want and if you see something that needs to be edited then you can do it if you want to. As you know, editing is important for keeping questions and answers clear, relevant, and up-to-date. If you are not comfortable with the idea of your contributions being collaboratively edited by other trusted users, this may not be the site for you.
And you can remind a user which link is a correct guidance or not, that depends on each user to do that. You can see yourself which post need to be edited, no need for a section to tell you when a post need to be edited. And as for links, they are important to be posted on the post, so that the users will know where you got these informations. That’s in my opinion.
I hope this is a good answer. If there’s anything wrong please let me know.