Doesn't look like that article says anything about trumpets to me. It does link to this article about horns, though: https://en.m.wikipedia.org/wiki/Horn_(instrument)

That one says:

In horns, unlike some other brass instruments such as the trumpet, the bore gradually increases in width through most of its length—that is to say, it is conical rather than cylindrical.[1]

Which seems to specifically exclude trumpets from horns.