I don't really see any reason to do so, and I'd generally avoid it just in case. If you are absolutely, 100% sure that the commented line has absolutely nothing to do with the question, go ahead and edit it out. But you have to be 100% sure, not 99.99999%.
Keep in mind that if you suggest an edit like that, it's very, very likely to get rejected, simply because changes to a user's code tend to be incorrect, and people don't usually look past that. Combine that with the fact that it's very minor.
So, to summarize: you probably should just let it go. Most people won't even include random comments like that unless they're relevant to the question. If not, it's one line; no big deal.