In #3708, we added formatters for the the convenience methods in the
`probs` package.
However, in #4783, @alexzorin pointed out that we were incorrectly
passing an error message through fmt.Sprintf as the format parameter
rather than as a value parameter.
I proposed a fix in #4784, but during code review we concluded that the
underlying problem was the pattern of using format-style functions that
don't have some variant of printf in the name. That makes this wrong:
`probs.DNS(err.Error())`, and this right: `probs.DNS("%s", err)`. Since
that's an easy mistake to make and a hard one to spot during code review,
we're going to stop using this particular pattern and call `fmt.Sprintf`
directly.
This PR reverts #3708 and adds some `fmt.Sprintf` where needed.
4a2029b293