In this question I made an answer and @illustro also provided an answer which includes information that I feel would improve my answer (I made a similar point in my answer, but his answer provided validation to that point).
I didn't want to 'steal his thunder' by appropriating the important part of his answer, but am wondering what the correct approach to this is?
If you really think that the information that @illustro pointed you to would improve your answer, definitely incorporate it. We want to create the best resource possible for the millions who will come after the original querent, and we know eyeballs drop off exponentially as they travel down the page. So, by all means: get the best info into your answer.
In cases like this I've made explicit reference to the answer that helped me improve mine, along the lines of:
Here's my thinking. Here's my explanation. @illustro points out in [their answer] (link) that "much better evidence here!" (Thanks, illustro! And you, Dear Reader, should definitely upvote their answer if you liked mine. I did!) Continuing my answer....
@username in an answer or question doesn't ping the user. (It actually doesn't do anything.) If a link to the user's material can't be provided (e.g. a deleted comment) then better to link to the user's profile directly to show the user's credibility. (Also see this question.)
\$\endgroup\$
Commented
Oct 8, 2019 at 18:58
If someone else's answer highlighted something you forgot to mention or expanded on a point your own answer made its perfectly fine to also incorporate that information in an edit.
The only unacceptable way to do this is to simply carbon copy another answer entirely.
