Consider reporting on variadic arity

[lread]

When v1 has

(defn variadic-loss [a b c & more])

And v2 has

(defn variadic-loss [a b])

The loss of the variadic signature could be reported, maybe like so:

test-resources/older/example.clj:x:y: error: example/variadic-loss variadic arity was removed.

If v1 and v2 were swapped, we do have a signature difference but don't technically have a signature breakage and so would not report.

[borkdude]

Agreed.