Show proper unapply signature help

[tgodzik]

Compiler version

3.1.2

Minimized code

class Two[A, B](a: A, b: B)
object Two {
  def unapply[A, B](t: Two[A, B]): Option[(A, B)] = None
}

object Main {
  val tp = new Two(1, "") 
  tp match {
    case Two(@@) =>
  }
}

Output

Signature help at @@ is showing

def unapply[A, B](t: Two[A, B]): Option[(A, B)] 
                  ^^^^^^^^^^^

Expectation

(Int, String)
 ^^^

[tgodzik]

Related PR in Metals: scalameta/metals#3862