Remove a wrong type argument in IO.interpret

In a compiler patch that changes the way type variables are maximised in
typedUnapply the code would throw the following type error:

    .handleError(t => Right((t.asLeft[IO[B]], limit - 1)))
    //                       ^^^^^^^^^^^^^^^
    // Found:    Either[Throwable, cats.effect.IO[B]]
    // Required: B
    //
    // where:    B is a type in methodinterpret with bounds >: Either[Throwable, A$1]

Turns out the right type argument for the RHS of Either is A, not IO[B],
and it's only because that type variable was instantiated to Any or
Nothing was it fine to use `IO[B]` instead.  Additionally there's some
kind of type inference interaction with the choice of Right.apply and
asRight, which I didn't look into further - I just switched to using asRight.

Author: dwijnand

core/shared/src/main/scala/cats/effect/IO.scala

@@ -927,7 +927,7 @@ sealed abstract class IO[+A] private () extends IOPlatform[A] {
                 case Left(_) => Left(io)
                 case Right((a, limit)) => Right((a.asRight[Throwable], limit))
               }
-              .handleError(t => Right((t.asLeft[IO[B]], limit - 1)))
+              .handleError(t => (t.asLeft, limit - 1).asRight)
 
           case IO.HandleErrorWith(ioe, f, _) =>
             interpret(ioe, limit - 1)