I've gotten a couple of edits for review where the editor has simply apparently tacked on several sentences' worth of information. Here is an example. It seems to me that this is appropriate for a comment -- but what is the workflow for migrating it to a comment? Or should I approve it if I feel it's accurate? (In most of these cases, I'm not knowledgeable enough to judge).
Is there a way I can message the editor to indicate that the additions are more appropriate for a comment?
(In most of these cases, I'm not knowledgeable enough to judge).
If you don't think you have enough knowledge to make a definite decision on a review item (of any kind), press the "Skip" button and move onto the next item. Far better to make no decision than make the wrong one.
If you know that the edit is incorrect, reject it. The suggester will see the rejection message (should they bother to look) and as well as one the predefined reasons you can add your own.
Certainly feel free to skip it if you don't feel comfortable rejecting it. However, edits which substantially alter the intent of the author are not acceptable, and that's (generally) easy to decide without expertise in the topic.
Note that as well as utilizing the rejection message (as mentioned by ChrisF) you can @ping the author of an edit, even if it's rejected, as mentioned by Jeff Atwood in his answer to Allow post editor to see @comments directed at him on Stack Exchange Meta.
My rule of thumb for these cases:
Consider having seen those added lines when the question was originally asked. Would they have bothered you? Would they have appeared superfluous and out-of-place?
If so - skip or reject (and explain why!). If not - accept the edit.
