Make sure we still parse arbitrary expressions nested

Author: adampauls

tests/pos/splice-pat.scala

@@ -15,4 +15,4 @@ def oneLevel(expr: Expr[Any])(using Quotes): Expr[Int] = expr match
   case '{ foo(${MyMatcher(y@MyMatcher2())}) } => y
 
 def twoLevel(expr: Expr[Any])(using Quotes): Expr[Int] = expr match
-  case '{ foo(${MyMatcher('{ bar(${y@MyMatcher2()})}) }) } => y
+  case '{ foo(${MyMatcher('{ bar(${y@MyMatcher2()}).getClass}) }) } => y