Patch welcome.

1. A code-font ... looks too much like the actual C++ ... token. As we start accepting that in more places, this is going to get more and more confusing. Commenting them out seems preferable.

2. /* ... */ is formatted very differently from // ...; the former remains in code font whereas the latter automatically transitions to roman italic typeface. We should investigate whether we can make listings do that for /* ... */ comments too, and whether that looks better.

3. The ..... mega-ellipses should be excised. These should be center dots for horizontal lists and vertical dots for vertical lists.

It would also be interesting to investigate using \vdots for places where we currently use commented-out ellipses.

@zygoloid: I'd like to revise item 3: ellipses should not just blanketly be "center dots", but rather, they should be the appropriate kind of dots for the things they apply to: center dots for binary operators like +, baseline dots for comma-separates items, etc. AmsTex has dedicated commands \dotsc (comma) and \dotsb (binary operator) for that; I think we should follow the same approach.