> * This is definitely not spam. But could it be considered a bit too much "affection" for Wikipedia by adding links that might not be relevant

The edition wasn't made for sole purpose of adding links, the author fixed grammar. The addition of links, I'd say, doesn't hurt the post, so if the editor like it, why not?

> * Are those links actually relevant? Do they improve the post?

I'd approach from the opposite side: they doesn't hurt the post. Do they improve it? Well, in the particular case it's subjective. But, they definitely doesn't hurt it.

> * Should these kinds of edits be:
	1. accepted without caring too much about them?
	2. encouraged because they provide useful background?
	3. rather rejected to avoid cluttering the post?

That depends. If the edit you linked would have made for sole purpose of adding links, I'd rather reject it, because it would add from little to no info to the post, and [trivial edits are discouraged](http://askubuntu.com/help/privileges/edit).

Another reject situation as if a post already has important links, like to bug-reports, blog posts, tutorials one used, etc; and the edition clutters available ones with those that didn't help much. As an upper bound situation imagine a post with every word linked to a dictionary.

In other cases, i.e. when edit was made for fixing purposes *(like grammar, formatting, etc)*, and links doesn't hurt to readability of the post, it is fine to accept.

As for the fact that links are made specifically to Wikipedia — I doesn't see it as anything bad at all: in the end, it is an encyclopedia, the more that it is free one.