Relax queue-related signatures to use QueueSink / QueueSource

[armanbilge]

Supersedes #2465

(GH wouldn't let me re-open the old PR)

[arosien]

Fixes #2437 I believe.

[kubukoz]

I'm just curious... I thought type erasure would consider these identical: okay I see, Queue and QueueSource aren't generics themselves so they'll end up as Queue and QueueSource in the bytecode. Obviously 😂

fs2/core/shared/src/main/scala/fs2/Stream.scala

Lines 3227 to 3245 in f855bf8

	def fromQueueUnterminated[F[_]: Functor, A](
	queue: QueueSource[F, A],
	limit: Int = Int.MaxValue
	): Stream[F, A] =
	fromQueueNoneTerminatedChunk_[F, A](
	queue.take.map(a => Some(Chunk.singleton(a))),
	queue.tryTake.map(_.map(a => Some(Chunk.singleton(a)))),
	limit
	)
	/** Returns a stream of elements from the supplied queue.
	*
	* All elements that are available, up to the specified limit,
	* are dequeued and emitted as a single chunk.
	*/
	def fromQueueUnterminated[F[_]: Functor, A](
	queue: Queue[F, A],
	limit: Int
	): Stream[F, A] = fromQueueUnterminated(queue: QueueSource[F, A], limit)

(also, shouldn't the second one be private[fs2]?)

[armanbilge]

@kubukoz I would have liked to, but marking it as private[fs2] still disappears the static forwarders :(

In fact, this was the problem in the original PR #2465.