Change the signature of Array.unapplySeq for the benefits of Scala 3

Fixes scala/scala3#14693, see discussion in the issue.

Author: smarter

src/library/scala/Array.scala

@@ -574,9 +574,9 @@ object Array {
    *  @param x the selector value
    *  @return  sequence wrapped in a [[scala.Some]], if `x` is an Array, otherwise `None`
    */
-  def unapplySeq[T](x: Array[T]): UnapplySeqWrapper[T] = new UnapplySeqWrapper(x)
+  def unapplySeq[T](x: Array[_ <: T]): UnapplySeqWrapper[T] = new UnapplySeqWrapper(x)
 
-  final class UnapplySeqWrapper[T](private val a: Array[T]) extends AnyVal {
+  final class UnapplySeqWrapper[T](private val a: Array[_ <: T]) extends AnyVal {
     def isEmpty: false = false
     def get: UnapplySeqWrapper[T] = this
     def lengthCompare(len: Int): Int = a.lengthCompare(len)